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Prognostic impact of perihepatic lymph node metastases in patients with resectable colorectal liver metastases. Br J Surg 2018; 105:1200-1209. [PMID: 29664996 DOI: 10.1002/bjs.10822] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/11/2017] [Accepted: 12/13/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Although perihepatic lymph node metastases (PLNMs) are known to be a poor prognosticator for patients with colorectal liver metastases (CRLMs), optimal management remains unclear. This study aimed to determine the risk factors for PLNMs, and the survival impact of their number and location in patients with resectable CRLMs. METHODS Data on patients with CRLM who underwent hepatectomy during 2003-2014 were analysed retrospectively. Recurrence-free (RFS) and overall (OS) survival were calculated according to presence, number and location of PLNMs. Risk factors for PLNM were evaluated by logistic regression analysis. RESULTS Of 1485 patients, 174 underwent lymphadenectomy, and 54 (31·0 per cent) had PLNM. Ten patients (5·7 per cent) who had lymphadenectomy and 176 (13·4 per cent) who did not underwent repeat hepatectomy. Survival of patients with PLNM was significantly poorer than that of patients without (RFS: 5·3 versus 13·8 months, P < 0·001; OS: 20·5 versus 71·3 months; P < 0·001). Median OS was significantly better in patients with para-aortic versus hepatoduodenal ligament PLNMs (58·2 versus 15·5 months; P = 0·011). Patients with three or more PLNMs had significantly worse median OS than those with one or two (16·3 versus 25·4 months; P = 0·039). The presence of primary tumour lymph node metastases (odds ratio 2·35; P = 0·037) and intrahepatic recurrence requiring repeat hepatectomy (odds ratio 5·61; P = 0·012) were significant risk factors for PLNM on multivariable analysis. CONCLUSION Patients undergoing repeat hepatectomy and those with primary tumour lymph node metastases are at significant risk of PLNM. Although PLNM is a poor prognostic factor independent of perihepatic lymph node station, patients with one or two PLNMs have a more favourable outcome than those with more PLNMs.
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Differential diagnosis of liver tumours using intraoperative real-time tissue elastography. Br J Surg 2014; 102:246-53. [DOI: 10.1002/bjs.9728] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 06/27/2014] [Accepted: 10/31/2014] [Indexed: 12/21/2022]
Abstract
Abstract
Background
Real-time tissue elastography is an innovative tool that informs the surgeon about tissue elasticity by applying the principle of ultrasonography. The aim of this study was to investigate the accuracy of intraoperative real-time tissue elastography (IORTE) for the detection and characterization of liver tumours.
Methods
Between October 2010 and November 2011, IORTE was performed for liver lesions after the completion of routine B-mode intraoperative ultrasonography (IOUS). The elasticity images of all tumours, except those of cysts, were classified into six categories according to modified criteria (types 1–6), according to the degree of strain contrast with the surrounding liver. The concordance of IORTE with pathological examination of the tumour, B-mode IOUS and clinical diagnosis after follow-up was assessed.
Results
Images were obtained from 92 hepatocellular carcinomas (HCCs), 92 adenocarcinomas, 19 other malignant tumours and 18 benign tumours in 158 patients. Using a minilinear probe, 73 of 88 HCCs were classified as having a ‘HCC pattern’ (type 3, 4 or 5), resulting in a sensitivity of 83·0 per cent, a specificity of 67·2 per cent and an accuracy of 73·7 per cent. Some 66 of 90 adenocarcinomas were classified as ‘adenocarcinoma pattern’ (type 6), resulting in a sensitivity of 73·3 per cent, specificity of 95·1 per cent and accuracy of 85·9 per cent. IORTE detected seven new lesions (8 per cent).
Conclusion
IORTE is useful for the detection and characterization of liver tumours.
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Discrimination of porcine glycogen debranching enzyme isozymes by the ratios of their 4- -glucanotransferase and amylo- -1,6-glucosidase activities. J Biochem 2010; 147:851-6. [DOI: 10.1093/jb/mvq019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Glycogen debranching enzyme was partially purified from bovine brain using a substrate for measuring the amylo-1,6-glucosidase activity. Bovine cerebrum was homogenized, followed by cell-fractionation of the resulting homogenate. The enzyme activity was found mainly in the cytosolic fraction. The enzyme was purified 5,000-fold by ammonium sulfate precipitation, anion-exchange chromatography, gel-filtration, anion-exchange HPLC, and gel-permeation HPLC. The enzyme preparation had no alpha-glucosidase or alpha-amylase activities and degraded phosphorylase limit dextrin of glycogen with phosphorylase. The molecular weight of the enzyme was 190,000 and the optimal pH was 6.0. The brain enzyme differed from glycogen debranching enzyme of liver or muscle in its mode of action on dextrins with an alpha-1,6-glucosyl branch, indicating an amino acid sequence different from those of the latter two enzymes. It is likely that the enzyme is involved in the breakdown of brain glycogen in concert with phosphorylase as in the cases of liver and muscle, but that this proceeds in a somewhat different manner. The enzyme activity decreased in the presence of ATP, suggesting that the degradation of brain glycogen is controlled by the modification of the debranching enzyme activity as well as the phosphorylase.
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Abstract
The structures of N-glycans of human blood clotting factor IX were studied. N-Glycans liberated by hydrazinolysis were N-acetylated and the reducing-end sugar residues were tagged with 2-aminopyridine. The pyridylamino (PA-) sugar chains thus obtained were purified by HPLC. Each PA-sugar chain was analyzed by two-dimensional sugar mapping combined with glycosidase digestion. The major structures of the N-linked sugar chains of human factor IX were found to be sialotetraantennary and sialotriantennary chains with or without fucose residues. These highly sialylated sugar chains are located on the activation peptide of the protein.
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Abstract
A processing The processing pathway of N-glycans in Carica papaya was deduced from the structures of N-glycans. The N-glycans were liberated by hydrazinolysis followed by N-acetylation. Their reducing-end sugar residues were tagged with 2-aminopyridine and the pyridylamino (PA-) sugar chains thus obtained were purified by HPLC. Eleven PA-sugar chains were found, and their structures were analyzed by two-dimensional sugar mapping combined with partial acid hydrolysis and exoglycosidase digestion. The structures of the N-glycans were of the highmannose types with xylose and fucose; however, among them two new N-glycans, Manalpha1-6(Manalpha1-3)Manalpha1-6(Xylbeta1-2)+ ++Manbeta1-4GlcNAcbeta1- 4(Fucalpha1-3)GlcNAc and Manalpha1-3Manalpha1-6(Xylbeta1-2)Manbeta1-4G lcNAcbeta1-4(Fucalpha1-3 )GlcNAc, were found. Judging from these structures together with Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) (Xylbeta1-2)Manbeta1- 4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc reported previously [Shimazaki, A., Makino, Y., Omichi, K., Odani, S., and Hase, S. (1999) J. Biochem. 125, 560- 565], a processing pathway for N-glycans in C. papaya is inferred in which the activity of Golgi alpha-mannosidase II is incomplete.
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Heterogeneous mutations in the glycogen-debranching enzyme gene are responsible for glycogen storage disease type IIIa in Japan. Hum Genet 2000; 106:108-15. [PMID: 10982190 DOI: 10.1007/s004390051017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Glycogen storage disease type IIIa (GSD IIIa) is an autosomal recessive disorder caused by deficiency of the glycogen-debranching enzyme (AGL). Recent studies of the AGL gene have revealed the prevalent mutations in North African Jewish and Caucasian populations, but whether these common mutations are present in other ethnic groups remains unclear. We have investigated eight Japanese GSD IIIa patients from seven families and identified seven mutations, including one splicing mutation (IVS 14+1G-->T) previously reported by us, together with six novel ones: a nonsense mutation (L124X), a splice site mutation (IVS29-1G-->C), a 1-bp deletion (587delC), a 2-bp deletion (4216-4217delAG), a 1-bp insertion (2072-2073insA), and a 3-bp insertion (4735-4736insTAT). The last mutation results in insertion of a tyrosine residue at a putative glycogen-binding site, and the rest are predicted to cause synthesis of truncated proteins lacking the glycogen-binding site at the carboxyl terminal. Thirteen novel polymorphisms have also been revealed in this study: three amino acid substitutions (R387Q, G1115R, and E1343 K), one silent point mutation (L298L), one nucleotide change in the 5'-noncoding region, and eight nucleotide changes in introns. Haplotype analysis with combinations of these polymorphic markers showed L124X, IVS14+1G-->T, and 4216-4217delAG to be on different haplotypes. These results demonstrate the importance of the integrity of the carboxy terminal domain in the AGL protein and the molecular heterogeneity of GSD IIIa in Japan.
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Heterogeneous mutations in the glycogen-debranching enzyme gene are responsible for glycogen storage disease type IIIa in Japan. Hum Genet 2000. [DOI: 10.1007/s004399900194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
The structure of a sugar chain of the proteinase inhibitor from the latex of Carica papaya was studied. Sugar chains liberated on hydrazinolysis were N-acetylated, and their reducing-end residues were tagged with 2-aminopyridine. One major sugar chain was detected on size-fractionation and reversed-phase HPLC analyses. The structure of the PA-sugar chain was determined by two-dimensional sugar mapping combined with sequential exoglycosidase digestion and partial acid hydrolysis, and by 750 MHz 1H-NMR spectroscopy. The structure found was Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) (Xylbeta1-2)Manbeta1- 4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc. This sugar chain represents a new plant-type sugar chain with five mannose residues.
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Abstract
The N-linked sugar chains, GlcNAcbeta1-2Manalpha1-6(GlcNAcbeta1-4)(Manalpha1++ +-3)Manbeta1-4GlcNAcb eta1-4(Fucalpha1-6)GlcNAc (BA-1) and GlcNAcbeta1-2Manalpha1-6(GlcNAcbeta1-4)(GlcNAcbeta1 -2Manalpha1-3)Manb eta1-4GlcNAcbeta1-4(Fucalpha1-6)GlcNAc (BA-2), were recently found to be linked to membrane proteins of mouse brain in a development-dependent manner [S. Nakakita, S. Natsuka, K. Ikenaka, and S. Hase, J. Biochem. 123, 1164-1168 (1998)]. The GlcNAc residue linked to the Manalpha1-3 branch of BA-2 is lacking in BA-1 and the removal of this GlcNAc residue is not part of the usual biosynthetic pathway for N-linked sugar chains, suggesting the existence of an N-acetyl-beta-D-hexosaminidase. Using pyridylaminated BA-2 (BA-2-PA) as a substrate the activity of this enzyme was found in all four subcellular fractions obtained. The activity was much greater in the cerebrum than in the cerebellum. To further identify the N-acetyl-beta-D-hexosaminidase, BA-1 and BA-2 in brain tissues of Hex gene-disrupted mutant mice were detected and quantified. PA-sugar chains were liberated from the cerebrum and cerebellum of the mutant mice by hydrazinolysis-N-acetylation followed by pyridylamination. PA-sugar chains were separated by anion-exchange HPLC, size-fractionation, and reversed-phase HPLC. Each peak was quantified by measuring the peaks at the elution positions of authentic BA-1-PA and BA-2-PA. BA-2-PA was detected in all the PA-sugar chain fractions prepared from Hexa, Hexb, and both Hexa and Hexb (double knockout) gene-disrupted mice, but BA-1 was not found in the fractions from Hexb gene-disrupted and double knockout mice. These results indicate that N-acetyl-beta-D-hexosaminidase B encoded by the Hexb gene hydrolyzed BA-2 to BA-1.
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11
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Analysis of oligosaccharide structures from the reducing end terminal by combining partial acid hydrolysis and a two-dimensional sugar map. Anal Biochem 1998; 264:172-9. [PMID: 9866679 DOI: 10.1006/abio.1998.2848] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A new sensitive and convenient method for the structural analysis of oligosaccharides was developed, in which partial acid hydrolysis was combined with two-dimensional sugar mapping of pyridylamino (PA)-oligosaccharides. A PA-oligosaccharide was partially hydrolyzed, the acid hydrolysis conditions being optimized so as to obtain various PA-oligosaccharide fragments with high yields from different types of PA-oligosaccharides. The acid hydrolyzates were then fractionated every 1 glucose unit by size-fractionation HPLC, and each fraction was analyzed by reversed-phase HPLC. The structure of each PA-oligosaccharide fragment was identified on a two-dimensional sugar map prepared with standard PA-sugar chains, after which the original PA-oligosaccharide was reconstructed from the reducing end terminal based on the obtained structures of the PA-oligosaccharide fragments. The method was successfully applied to resolving the structure of an N-linked sugar chain.
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12
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An assay method for glycogen debranching enzyme using new fluorogenic substrates and its application to detection of the enzyme in mouse brain. J Biochem 1998; 123:932-6. [PMID: 9562628 DOI: 10.1093/oxfordjournals.jbchem.a022027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
An assay method for glycogen debranching enzyme involving fluorogenic dextrins as substrates was developed. Two dextrins were prepared from 6-O-alpha-D-glucosyl-alpha-cyclodextrin and glucose by taking advantage of the action of Bacillus macerans cyclodextrin glucanotransferase, and converted by pyridylamination to fluorogenic derivatives. Structural analysis of the fluorogenic dextrins by FAB-MS, partial acid hydrolysis, and glucoamylase digestion revealed that they were Glcalpha1-4(Glcalpha1-6)Glcalpha1-4Glcalpha1- 4Glcalpha1-4Glc-PA (FD6) and Glcalpha1-4Glcalpha1-4(Glcalpha1-6)Glcalpha1- 4Glcalpha1-4Glcalpha1-4G lc-PA (FD7). Using the glycogen debranching enzyme from rabbit muscle, FD6 and FD7 were, respectively, hydrolyzed to PA-maltopentaose and PA-maltohexaose, in addition to glucose, showing that these two fluorogenic dextrins are suitable substrates for assaying the glycogen debranching enzyme. An assay method involving the separation and quantification by HPLC of the characteristic fluorogenic products was successfully applied to determination of the distribution of the enzyme activity in mouse cerebrum.
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13
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Introduction of a new scale into reversed-phase high-performance liquid chromatography of pyridylamino sugar chains for structural assignment. J Chromatogr A 1998; 800:187-98. [PMID: 9561762 DOI: 10.1016/s0021-9673(97)01109-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Addition of a monosaccharide residue to a pyridylaminated (PA)-N-linked sugar chain results in an increment or decrement in the elution time on reversed-phase HPLC, the difference being defined as the partial elution time of the residue. Based on this principle, an empirical rule was deduced, which states that the elution time is roughly equal to the sum of the partial elution times of the component sugar residues [Anal. Biochem., 167 (1987) 321-326]. In practice, however, some partial elution times obtained from different pairs of mother PA-sugar chains are found to deviate, and consequently the closeness of the elution times of PA-sugar chains calculated therefrom to the observed times is reduced in such cases. To improve the reliability of the additivity rule and to generalize elution times so that they are less dependent on minor alterations in the elution conditions, we have devised a new scale for elution time, which we have named a reversed-phase scale. The elution times on the reversed-phase scale (the R values) are read from a conversion curve constructed using the elution times of eight selected standard PA-sugar chains. The partial elution times on the reversed-phase scale of 22 monosaccharide residues were calculated from the R values of 93 PA-sugar chains. The R values obtained by summing the partial elution times of all the component monosaccharide residues became much closer to the R values obtained from the reversed-phase scale, compared to the results obtained using the previous method. In addition, the R values were less influenced by minor change in the elution conditions. These features of the new scale allow more accurate structural assignment of sugar chains.
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Presence of UDP-D-xylose: beta-D-glucoside alpha-1,3-D-xylosyltransferase involved in the biosynthesis of the Xyl alpha 1-3Glc beta-Ser structure of glycoproteins in the human hepatoma cell line HepG2. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 245:143-6. [PMID: 9128735 DOI: 10.1111/j.1432-1033.1997.00143.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
HepG2 cells were examined for the presence of UDP-D-xylose: beta-D-glucoside alpha-1,3-xylosyltransferase activity by using 2-[(2-pyridyl)amino]ethyl beta-D-glucopyranoside (Glc beta-R) as a fluorogenic acceptor. UDP-D-xylose and the acceptor were incubated with the HepG2 microsomal fraction, and the enzymatic reaction mixture was analyzed by HPLC. Structural analysis of the fluorogenic product by alpha-D-xylosidase digestion, FAB-MS, and Smith degradation revealed that it was Xyl alpha 1-3Glc beta-R, thus demonstrating the existence of beta-D-glucoside alpha-1,3-xylosyltransferase. A solubilization study of the enzyme from the microsomal fraction indicated that it differed from UDP-D-xylose: alpha-D-xylodie alpha-1,3-xylosyltransferase of the HepG2 microsomal fraction producing Xyl alpha 1-3Xyl alpha 1-3Glc-R' [R', (2-pyridyl)amino-] from UDP-D-xylose and Xyl alpha 1-3Glc-R' [Minamida, S., Aoki, K., Natsuka, S., Omichi, K., Fukase, K., Kusumoto, S. & Hase, S. (1996) J. Biochem. (Tokyo) 120, 1002-1006]. The newly detected enzyme appears to be involved in the biosynthesis of the Xyl alpha 1-3Glc beta-Ser structure of glycoproteins such as human blood coagulation factors VII and IX.
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Detection of UDP-D-xylose: alpha-D-xyloside alpha 1-->3xylosyltransferase activity in human hepatoma cell line HepG2. J Biochem 1996; 120:1002-6. [PMID: 8982869 DOI: 10.1093/oxfordjournals.jbchem.a021492] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We previously reported the detection of novel O-linked sugar chains classified as being of the glucosyl-O-serine type [Hase et al. (1988) J. Biochem. 104, 867-868]. The sugar chains are a disaccharide (Xyl alpha 1-3Glc) and a trisaccharide (Xyl alpha 1-3Xyl alpha 1-3 Glc) linked to serine residues in epidermal growth factor-like domains of human and bovine blood coagulation factors. The structures of these sugar chains suggested the presence of an alpha 1-->3xylosyltransferase for their biosynthesis. We report here on the detection of alpha 1-->3xylosyltransferase activity which catalyzes the transfer of xylose to Xyl alpha 1-3Glc in the human hepatoma cell line HepG2. We employed pyridylaminated Xyl alpha 1-3Glc as a fluorescent acceptor and UDP-D-Xyl as a donor. The reaction product was purified by reversed-phase HPLC, and the structure of the transfer product isolated was confirmed to be pyridylaminated Xyl alpha 1-3Xyl alpha 1-3Glc by Smith degradation, mass spectrometry, and alpha- and beta-xylosidase digestions. The apparent K(m) value for pyridylaminated Xyl alpha 1-3Glc was 52 mM and for UDP-D-Xyl 0.28 mM. Optimum pH was 7.2. The enzyme was inactivated by addition of EDTA, and its activity was restored by addition of Mn2+ and Mg2+. These results indicate the presence of a novel enzyme which is able to transfer xylose to Xyl alpha 1-3Glc, forming Xyl alpha 1-3Xyl alpha 1-3Glc in human cells.
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Abstract
A method for preparing neoglycolipids possessing a sugar chain with a definite structure using two N-linked sugar chains as model compounds was developed. Pyridylaminated sugar chains obtained from glycoproteins were purified by reversed-phase HPLC and a pyridylaminated sugar chain thus obtained was converted to a 1-amino-1-deoxy derivative. The product was conjugated by reductive amination with phosphatidylglycolaldehyde prepared by periodate oxidation of dipalmitoyl phosphatidylglycerol. Neoglycolipids formed were purified by gel filtration from the reaction mixture. The structures of the purified neoglycolipids were confirmed by composition analysis for sugar, fatty acid, phosphorus, and 2-acetamido-1,2-dideoxy-1-[(hydroxyethyl)amino]-D-glucitol, the linkage region of the sugar chain, and lipid moieties. The method provides a convenient means of preparing neoglycolipids having a definite structure.
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Classification of sugar chains of glycoproteins by analyzing reducing end oligosaccharides obtained by partial acid hydrolysis. Anal Biochem 1996; 238:54-9. [PMID: 8660586 DOI: 10.1006/abio.1996.0250] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Sugar chain types were classified on the basis of reducing end di- and trisaccharide structures. Sugar chains liberated from glycoproteins by the hydrazinolysis-N-acetylation method were pyridylaminated, and pyridylamino (PA-) sugar chains were purified by HPLC. The PA-sugar chains thus purified were partially hydrolyzed with 1 M trifluoroacetic acid. The acid hydrolysis conditions were investigated with the object of obtaining PA-di- and trisaccharides with high yields for different types of PA-sugar chains. The acid hydrolysates were separated by size-fractionation HPLC into PA-mono-, PA-di-, and PA-trisaccharides, and each fraction was analyzed by reversed-phase HPLC. The structures were then identified by comparing the HPLC elution positions with those of authentic PA-oligosaccharides derived from N-linked sugar chains and 12 types of O-linked sugar chains.
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Abstract
A cytosolic neutral alpha-mannosidase was purified from bovine liver. Its molecular weight was found to be 500,000 on gel filtration. The activity of the enzyme toward Man alpha 1-6-(Man alpha 1-3)Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc-PA was increased 26-fold by preincubation with 1 mM Co2+. Man alpha 1-6(Man alpha 1-3)Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc was hydrolyzed by the enzyme to Man alpha 1-3Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc, which was further hydrolyzed to Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc. The rate of hydrolysis was 15-fold greater than that of Man alpha 1-6(Man alpha 1-3)Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4GlcNAc. This substrate specificity suggested that the enzyme could be involved in the degradation of oligomannose-type sugar chains with one GlcNAc residue released from glycoproteins by endo-beta-N-acetylglucosaminidase, and supported a pathway for glycoprotein catabolism via oligomannosyl glycans with one GlcNAc residue proposed on the basis of an earlier study on a cytosolic neutral alpha-mannosidase from Japanese quail oviduct [Oku, H. and Hase, S. (1991) J. Biochem. 110, 982-989].
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Determination of the linkage positions of reducing-end residues of oligosaccharides by partial periodate oxidation of pyridylaminated derivatives. Anal Biochem 1995; 227:404-7. [PMID: 7573970 DOI: 10.1006/abio.1995.1304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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A new disaccharide Fuc alpha 1-2Man found in human urine. J Biochem 1994; 115:927-9. [PMID: 7961608 DOI: 10.1093/oxfordjournals.jbchem.a124440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Human urine collected from healthy individuals was ultrafiltered and the filtrate was gel-filtered. The fraction including disaccharides was pyridylaminated to convert the reducing sugars to fluorescent pyridylamino (PA)-derivatives. A PA-disaccharide consisting of Fuc and Man was purified by gel filtration, reversed-phase HPLC, and size fractionation HPLC. Structural analysis revealed that the disaccharide was Fuc alpha 1-2Man-PA. The disaccharide is considered to be a metabolite of unknown glycoconjugates.
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Identification of trisaccharide Xyl alpha 1-->3Xyl alpha 1-->3Glc in human urine. Biosci Biotechnol Biochem 1994; 58:567-9. [PMID: 7764696 DOI: 10.1271/bbb.58.567] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Oligosaccharides in human urine were converted to pyridylamino (PA)-derivatives. From the PA-oligosaccharides, a saccharide that was chromatographically identical with a synthetic standard, Xyl-alpha 1-->3Xyl alpha 1-->3Glc-PA, was isolated by gel filtration and HPLC. Structure analysis showed that the saccharide was Xyl alpha 1-->3Xyl-alpha 1-->3Glc-PA. It is likely that Xyl alpha 1-->3Xyl alpha 1-->3Glc originated from such glycoconjugates as blood coagulation factors VII and IX, and protein Z.
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Linkage position analysis of pyridylamino-disaccharides by HPLC of fluorogenic Smith degradation products. J Biochem 1994; 115:429-34. [PMID: 8056754 DOI: 10.1093/oxfordjournals.jbchem.a124355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Oligosaccharides are often converted to fluorogenic pyridylamino-oligosaccharides (PA-oligosaccharides) to be analyzed sensitively. A method for determining the glycosidic linkage position to the PA-reducing-end residue was developed with PA-disaccharides as model compounds. Periodate oxidation of PA-disaccharides was carried out at 0 degrees C for 15 min or at 4 degrees C for 40 h, and the reaction mixtures were reduced with borohydride. The fluorogenic products obtained at 4 degrees C for 40 h were purified by reversed phase HPLC, and the fraction collected were hydrolyzed with acid. The hydrolysates were analyzed by reversed phase HPLC. PA-glyceraldehyde was formed from 2-substituted PA-disaccharides with PA-hexose, PA-threose (or PA-erythrose) from 3-substituted ones, and PA-glycolaldehyde from 4- or 6-substituted ones. HPLC analysis of the products obtained at 0 degrees C for 15 min revealed a difference between 4- and 6-substituted ones. PA-glyceraldehyde was formed from 6-substituted ones, but not from 4-substituted ones. The linkage position, therefore, can be determined by analyzing fluorogenic product(s). As for PA-disaccharides with PA-N-acetylglucosamine, the linkage position can be simply determined by analysis of 40-h oxidation-reduction mixtures. 2-Acetamido-2-deoxy derivatives of PA-threose, PA-xylose, and PA-glyceraldehyde were formed from 3-, 4-, and 6-substituted ones, respectively. The linkage position analysis was successfully applied to determination of the structures of two Fuc-Man-PAs produced through the transglycosylation action of bovine kidney alpha-L-fucosidase.
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Identification of the characteristic amino-acid sequence for human alpha-amylase encoded by the AMY2B gene. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1203:224-9. [PMID: 8268204 DOI: 10.1016/0167-4838(93)90087-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Human salivary and pancreatic alpha-amylases (HSA and HPA) are the respective gene products of the AMY1 and AMY2A genes. AMY2B is a newly found human alpha-amylase gene. The presence of the AMY2B gene product (HXA) in the urine of healthy humans was examined. A mixture of alpha-amylases that seemed to contain HXA, judging from the substrate specificity, was purified from urine of healthy volunteers by affinity adsorption on starch and then by ion-exchange chromatography. The mixture was reduced and S-alkylated, and the product was digested with trypsin. The digest was separated by reversed-phase HPLC. LVGLLDLALEKDYVR and LVGLLDLALEK, which were found in the digest, are peptides of HXA, but not of HSA and HPA. The detection of these characteristic peptides of HXA demonstrates the presence of HXA in the urine of healthy humans.
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Abstract
Type and structural analysis of O-linked sugar chains in human blood clotting factor IX was performed by the pyridylamination method developed for O-linked sugar chains [Kuraya, N. & Hase, S. (1992) J. Biochem. 112, 122-126]. O- and N-linked sugar chains were released with hydrazine, and then N-acetylated, followed by pyridylamination. The type of sugar chain was determined by reducing-end analysis of the pyridylaminated (PA-) sugar chains. Sugar chains with PA-GalNAc at the reducing terminal and that with PA-Fuc [Nishimura, H. et al. (1992) J. Biol. Chem. 267, 17520-17525] were obtained besides known sugar chains with PA-Glc from the Xyl-Glc-Ser type and those with PA-GlcNAc from asparagine-linked sugar chains. The sugar chains with PA-GalNAc were identified as mono- and disialyl Gal beta 1-3GalNAc by two-dimensional HPLC mapping. The structure of the sugar chain with PA-Fuc was Neu5Ac alpha 2-6Gal beta 1-4GlcNAc beta 1-3Fuc, as determined by exoglycosidase digestion, methylation analysis, and Smith degradation.
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Abstract
The existence of alpha-amylase (HXA) encoded by alpha-amylase gene AMY2B in healthy humans was examined using a fluorogenic substrate, FG5P (FG-G-G-G-G-P: FG, 6-deoxy-6-[(2-pyridyl)amino]-D-glucose residue; G, glucose residue; P, p-nitrophenyl residue; -, alpha-1,4-glycosidic bond). Chromatofocusing of urine from a healthy human was carried out. FG5P was digested with the fractions exhibiting alpha-amylase activity and each digest at an early stage was analyzed by HPLC. FG5P was hydrolyzed to FG3 (FG-G-G) and p-nitrophenyl alpha-maltoside (G-G-P), and to FG4 (FG-G-G-G) and p-nitrophenyl alpha-glucoside (G-P). The molar ratios of FG4 to FG3 (FG4/FG3) in the digests with basic fractions were larger than those in the digests of human pancreatic alpha-amylase (HPA, 1.11) and human salivary alpha-amylase (HSA, 0.51). Considering that the value for the AMY2B gene product with yeast (yHXA) is 1.88, a value of more than 1.11 implies that HXA exists. The amount of HXA was determined after removal of HSA on an anti-human salivary alpha-amylase antibody bound column. The FG4/FG3 values for six urine samples free from HSA were 1.23-1.26. Assuming that the FG4/FG3 value for HXA is the same as that for yHXA, the ratios of HXA and HPA were estimated to be 1:5.4-4.1. The results obtained showed that the AMY2B gene is usually expressed as HXA in healthy humans.
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Studies on the active site of human alpha-amylases: examination of the third subsite S3' of the aglycone-binding site by control of substrate binding mode. J Biochem 1992; 111:4-7. [PMID: 1607363 DOI: 10.1093/oxfordjournals.jbchem.a123716] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Modified maltooligosaccharides, IG-G-G-G-AG-G (IG: 6-deoxy-6-iodo-D-glucopyranose residue, G: D-glucopyranose residue, AG: 6-amino-6-deoxy-D-glucopyranose residue, -: alpha-1,4-glycosidic linkage), IG-G-G-G-AG-M (M: methyl), and IG-G-G-G-AG-phi (phi: phenyl) were prepared by the use of cyclodextrin glucanotransferase in order to examine the third subsite (S3') of the aglycone-binding site of human salivary and pancreatic alpha-amylases. Human alpha-amylases hydrolyzed the modified maltooligosaccharides to IG-G-G and G-AG-G, IG-G-G and G-AG-M, and IG-G-G and G-AG-phi. This implied that G, M, and phi fit into S3'. There was no difference in the rate parameters between the two enzymes. The Km values for the hydrolysis of IG-G-G-G-AG-G by both enzymes were the same as those for IG-G-G-G-AG-M, and twice those for IG-G-G-G-AG-phi. The results showed that S3' of the two enzymes has no affinity for the glucose residue and is not a subsite but a hydrophobic environment.
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Investigation of the active site of Bacillus macerans cyclodextrin glucanotransferase by use of modified maltooligosaccharides. J Biochem 1991; 110:756-61. [PMID: 1838375 DOI: 10.1093/oxfordjournals.jbchem.a123654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The active site of Bacillus macerans cyclodextrin glucanotransferase (CGTase) was examined by use of derivatives of phenyl alpha-maltopentaoside and phenyl alpha-glucoside as the substrates and acceptors, respectively. The active site of this enzyme is considered to be composed of tandem subsites (S4, S3, S2, S1, S1', S2', etc.) geometrically complementary to several glucose residues, and the alpha-1,4-glycosidic linkage of a substrate is split between S1 and S1'. The features of subsites S3 and S4 of the glycon binding site were estimated from the modes of the enzymatic action on phenyl alpha-maltopentaoside (G-G-G-G-G-phi; G, glucose residue; phi, phenyl residue; -, alpha-1,4-glycosidic bond) and its derivatives in which the CH2OH groups of the non-reducing-end glucose residues were converted to CH2I (IG-G-G-G-G-phi; IG, 6-deoxy-6-iodo-D-glucose residue), CH2NH2 (AG-G-G-G-G-phi; AG, 6-amino-6-deoxy-D-glucose residue), or COOH (CG-G-G-G-G-phi; CG, glucuronic acid residue). p-Nitrophenyl alpha-glucopyranoside (G-P; P, p-nitrophenyl residue) was used as an acceptor. HPLC analysis of the digests revealed that the CG residue of CG-G-G-G-G-phi was excluded from subsite S3, while it was accommodated in subsite S4. The Km and Vmax values for CG-G-G-G-G-phi were remarkably larger and smaller, respectively, than those for any other substrates.(ABSTRACT TRUNCATED AT 250 WORDS)
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Immunohistochemical, ultrastructural and biochemical studies of an amylase-producing breast carcinoma. VIRCHOWS ARCHIV. A, PATHOLOGICAL ANATOMY AND HISTOPATHOLOGY 1991; 419:29-33. [PMID: 1712519 DOI: 10.1007/bf01600149] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We describe a breast cancer with ectopic production of amylase, found in the patient's serum, urine and in the tumour. Clinically, serum amylase levels reflected both the progression of the disease and regression induced by various therapies. Using agarose gel electrophoresis and a wheat protein inhibitor assay, the predominant serum amylase appeared to be identical to pancreatic-type isoenzyme. However, the action mode analysis using a new fluorogenic substrate revealed that the serum contained non-salivary, non-pancreatic amylase. The tumour had microscopic features of invasive ductal carcinoma with some argyrophilic differentiation. The component cells stained positively for amylase, and ultrastructurally numerous secretory granules were seen.
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Examination of aglycone-binding site of human salivary alpha-amylase by means of transglycosylation reactions. J Biochem 1991; 109:410-5. [PMID: 1880127 DOI: 10.1093/oxfordjournals.jbchem.a123395] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The active site of human salivary alpha-amylase is composed of tandem subsites (S3, S2, S1, S1',S2', etc.) geometrically complementary to several glucose residues, and the glycosidic linkage of the substrate is split between S1 and S1'. As a matter of convenience, the subsites to which the non-reducing-end part (glycone) and the reducing-end part (aglycone) of the substrate being hydrolyzed are bound are named the glycone-binding site (S3, S2, S1) and the aglycone-binding site (S1', S2'), respectively. The features of the aglycone-binding site of human salivary alpha-amylase were examined by means of transglycosylation reaction using phenyl alpha-maltoside (GG phi: G-G-phi) and its derivatives (GAG phi: G-AG-phi, GCG phi: G-CG-phi, AGG phi: AG-G-phi, and CGG phi: CG-G-phi) in which one of the glucose residues (G) has been converted to 6-amino-6-deoxy-glucose (AG) or glucuronic acid (CG) residue as the acceptor. A fluorogenic derivative of maltotetraose, p-nitrophenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha-D -glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-alpha-D- glucopyranosyl-(1----4)-alpha-D-glucopyranoside (FG4P, FG-G-G-G-P), was used as the substrate. HSA catalyzed both hydrolysis of FG4P to FG3 (FG-G-G) and p-nitrophenyl alpha-glucoside (G-P) and transfer of the FG3 residue of FG4P to the acceptors. Transfer to GAG phi occurred more effectively than to GG phi. Transfers to GCG phi and CGG phi were less than to GG phi and very little transfer to AGG phi occurred.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
A novel amylase gene (amy3) that differs in nucleotide sequence from salivary amylase gene (amy1) and pancreatic amylase gene (amy2) has been described [Tomita et al., Gene 76 (1989) 11-18], but whether this gene can ever code for an active enzyme has not been shown. We prepared cDNA of this gene from an mRNA obtained from lung carcinoid tissue, and expressed it in Saccharomyces cerevisiae under the control of an acid phosphatase promoter. The product was secreted into culture media, and showed enzymatic activity, demonstrating that this novel alpha-amylase gene (amy3) can code for a functional isozyme. We purified this enzyme, and compared its biological properties with those of salivary and pancreatic human amylases similarly expressed in yeast. We observed that the novel amylase isozyme is more heat-sensitive than others, and that its substrate specificity is different from the other two isozymes.
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Differentiation of human non-salivary, non-pancreatic alpha-amylase from salivary and pancreatic alpha-amylases by use of FG5P. J Biochem 1990; 107:546-9. [PMID: 2358428 DOI: 10.1093/oxfordjournals.jbchem.a123083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Human non-salivary, non-pancreatic alpha-amylase (yHXA) is the gene product of a newly found human alpha-amylase gene expressed in yeast. Its mode of action on a fluorogenic derivative of p-nitrophenyl alpha-maltopentaoside, FG5P (FG-G-G-G-G-P), was examined at various pH values to elucidate the difference between yHXA and pancreatic or salivary alpha-amylase. The product analysis of the digests by HPLC showed that the enzyme hydrolyzed FG5P to FG3 (FG-G-G) and p-nitrophenyl alpha-maltoside (G-G-P) and to FG4(FG-G-G-G) and p-nitrophenyl alpha-glucoside (G-P), and the ratio of the two reactions changed with pH. The three enzymes differed from each other in the mode of action at pH 5.5. The molar ratio of FG4 to FG3 in the digest with yHXA was the largest. This suggested that the expression of the new gene in human can be detected by the use of FG5P as the substrate in the alpha-amylase assay.
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Actions of three human alpha-amylases expressed in yeast on modified substrates and the amino acid residues causing their different actions. J Biochem 1989; 106:646-50. [PMID: 2691509 DOI: 10.1093/oxfordjournals.jbchem.a122910] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The mode of action of an alpha-amylase (yHXA) which was the gene product of a newly found human alpha-amylase gene expressed in yeast on synthetic substrates was compared with those of the gene products (yHSA and yHPA) of human salivary and pancreatic alpha-amylase gene in yeast. The substrates used were phenyl alpha-maltopentaoside (G5 phi) and its derivatives in which the CH2OH groups of the non-reducing-end glucose residues were converted to CH2NH2 (AG5 phi), COOH (CG5 phi), or CH2I (IG5 phi). The digests were subjected to HPLC to determine the amounts of products. The HPLC analysis revealed that yHXA and yHSA bound G5 phi to their active sites in similar manners to give the same products, while yHPA hydrolyzed it in a different way. Modifications of the non-reducing-end glucose of G5 phi caused change of the binding mode to the active sites of the enzymes. AG5 phi and CG5 phi were hydrolyzed by the enzymes to give more phenyl alpha-glucoside (G phi) and less phenyl alpha-maltoside (G2 phi), while IG5 phi gave more G2 phi and less G phi, compared with G5 phi. The substrate binding mode of yHXA changed more extensively than that of yHSA. The results suggested that there exists an amino acid replacement between yHXA and yHSA. The amino acid residues replaced are neither acidic nor basic, are located in subsite S3, and interact with the CH2OH residue of the non-reducing-end glucose residue of G5 phi.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
The course of the action of human salivary alpha-amylase (HSA) on a substrate was examined taking advantage of its transglycosylation action. IG5 phi (IG-G-G-G-G-phi), IG4 phi (IG-G-G-G-phi), and GIG4 phi (G-IG-G-G-G-phi) were used as the substrates and p-nitrophenyl alpha-glucoside (GP, G-P) as the acceptor. HSA hydrolyzes IG5 phi, IG4 phi, and GIG4 phi to IG3 (IG-G-G) and G2 phi (G-G-phi), to IG3 and G phi (G-phi), and to GIG3 (G-IG-G-G) and G phi, respectively. In the presence of GP, a part of the glycon residues, IG3 and GIG3, were transferred to the acceptor to give IG4P (IG-G-G-G-P) and GIG4P (G-IG-G-G-G-P), respectively. Whenever the enzyme attacks the substrate, G phi or G2 phi is liberated in both transglycosylation and hydrolysis. The extent of transglycosylation can be, therefore, estimated from the molar ratio of the transfer product to the liberated aglycon, G phi or G2 phi. HPLC analysis of the reaction mixtures revealed that the value of IG4P/G phi in the digest of IG4 phi was nearly equal to that of GIG4P/G phi in the digest of GIG4 phi and these values were ten times larger than that of IG4P/G2 phi in the digest of IG5 phi. These data suggested that G phi residue would fall away from aglycon binding site more rapidly than G2 phi residue after the cleavage of the alpha-1,4-glycosidic linkage to offer GP more chance to attack to the activated glycon and also indicated that the space of the glycon binding site corresponds to three glucose residues.
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A comparison of the modes of actions of human salivary and pancreatic alpha-amylases on modified maltooligosaccharides. J Biochem 1988; 104:667-70. [PMID: 2467909 DOI: 10.1093/oxfordjournals.jbchem.a122529] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The actions of three isozymes of human pancreatic alpha-amylase (HPA) on phenyl alpha-maltopentaoside, phenyl alpha-maltotetraoside, and their derivatives which have an iodo, an amino, or a carboxyl group at their first or penultimate glucopyranosyl residue from the non-reducing-end were examined. The results revealed that there was no difference in the actions of the three isozymes on the modified substrates and suggested the presence of five subsites (S3, S2, S1, S1', and S2') and a hydrophobic amino acid residue at subsite S3 in the active site of HPA. As compared with the action of human salivary alpha-amylase (HSA) on the same substrates, HPA had a tendency to release more phenyl alpha-glucoside from every substrate; however, an iodo, an amino, and a carboxyl group of the substrates had the same effects on the binding modes of the substrates to the active site of HPA as seen in the case of the salivary enzyme. This result indicates that the three-dimensional structures of the active sites of both alpha-amylases are quite similar except for some minor changes at subsites S3 and S2'.
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Investigation of the active site of human salivary alpha-amylase from the modes of action on modified maltooligosaccharides. J Biochem 1988; 104:409-15. [PMID: 3266496 DOI: 10.1093/oxfordjournals.jbchem.a122481] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The modes of action of two isozymes of human salivary alpha-amylase on phenyl alpha-maltopentaoside, phenyl alpha-maltotetraoside, and their derivatives which have an iodo or an amino or a carboxyl group at their first or penultimate glucopyranosyl residues from the non-reducing-end were examined. It is conceivable that the active site of this enzyme is composed of tandem subsites (S4,S3,S2,S1,S1',S2', and S3') geometrically complementary to several glucose residues, and that the glucosidic bonds of the substrates are split between S1 and S1'. Product analysis of each digest strongly suggested the presence of a hydrophobic amino acid residue at subsite S3 in the active site of the enzyme. No difference in the modes of action on the substrates was found between the two isozymes, indicating that the three-dimensional structures of their active site areas are, at the least, similar.
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Use of a post-column enzymatic reaction for detection of macroamylasemia by high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1988; 428:415-8. [PMID: 2463991 DOI: 10.1016/s0378-4347(00)83937-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Abstract
A new fluorogenic acceptor for sialyltransferase, 2-[(2-pyridyl)amino]ethyl O-beta-D-galactopyranosyl-(1----4)-beta-D-glucopyranoside, was prepared from lactose as a starting material. Sialyltransferase activity was assayed by incubation of the enzyme with the acceptor and CMP-N-acetylneuraminic acid, separation of the fluorogenic sialylated product from the enzymatic reaction mixture by HPLC, and measurement of the product. Compared to assays so far reported that use radioactive substrates, this assay is simple and rapid. This method was used to assay sialyltransferase activity in human serum.
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Alpha-amylase assay with use of a benzyl derivative of p-nitrophenyl alpha-maltopentaoside, BG5P. Clin Chim Acta 1988; 174:315-23. [PMID: 3134147 DOI: 10.1016/0009-8981(88)90058-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
p-Nitrophenyl O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1-- --4)-alpha-D-glucopyranoside (BG5P) is hydrolyzed by both human salivary alpha-amylase (HSA) and human pancreatic alpha-amylase (HPA) to O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-alpha-D-glucopyranose (BG3) and p-nitrophenyl alpha-maltoside (G2P). Glucoamylase and alpha-glucosidase cannot hydrolyze BG5P because of the modification of the OH group of the 6-position of the non-reducing-end glucose residue with the benzyl group. Taking advantage of these characteristics of the substrate, BG5P, we developed a method to assay the total alpha-amylase activity in human fluids using glucoamylase and alpha-glucosidase as the coupled enzymes. This method is simple and can be used as the standard method for routine clinical assays of alpha-amylase activity.
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Abstract
p-Nitrophenyl alpha-maltopentaoside, having a benzyl group on O-6 of the terminal (nonreducing) D-glucosyl group was prepared by use of a reductive ring-opening reaction. Highly regioselective reduction of p-nitrophenyl O-(2,3-di-O-benzoyl-4,6-O-benzylidene-alpha-D-glucopyranosyl)-(1----4)- tris[O-(2,3,6-tri-O-benzoyl-alpha-D-glucopyranosyl)-(1----4)]-2,3,6-tri- O- benzoyl-alpha-D-glucopyranoside by dimethylamine-borane and p-toluenesulfonic acid, followed by debenzoylation, gave p-nitrophenyl O-(6-O-benzyl-alpha-D-glucopyranosyl)-(1----4)-tris[O-alpha-D-glucopyran osyl- (1----4)]-alpha-D-glucopyranoside. An experiment was done on the mode of action of human pancreatic and salivary alpha amylases on this derivative. The compound is suitable as a substrate for the assay of alpha amylase when used with glucoamylase and alpha-D-glucosidase as coupling enzymes.
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Separation of human salivary alpha-amylase isozymes by high-performance liquid chromatography with a continuous monitor system of the activity. Anal Biochem 1988; 168:332-6. [PMID: 3259114 DOI: 10.1016/0003-2697(88)90326-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Human salivary alpha-amylase isozymes were rapidly separated from each other by high-performance liquid chromatography with a postcolumn assay. The eluate from the HPLC column was mixed continuously with an intramolecularly quenched fluorescent substrate, p-nitro-phenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-alpha-D-glucopyranoside delivered by a pump. The mixture was incubated in a reaction coil, and the fluorescence intensity was continuously measured by a fluorescence detector. The assay was based on the marked increase in fluorescence with the enzymatic cleavage of the glycosidic bond of the substrate that links the fluorogenic and quenching moieties.
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Studies on the active site of Taka-amylase A: its action on phenyl maltooligosides with a charge at their non-reducing-ends. J Biochem 1987; 102:767-75. [PMID: 3501785 DOI: 10.1093/oxfordjournals.jbchem.a122114] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Five modified moltooligosaccharides, phenyl O-6-amino-6-deoxy-alpha-D- glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1-- --4)- alpha-D-glucopyransoide (AG4P), phenyl O-(alpha-D-glucopyranosyluronic acid)-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-d-glucopyran osy l- (1----4)-alpha-D-glucopyranoside (CG4P), phenyl O-6-amino-6-deoxy-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyra nos yl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1-- --4)- alpha-D-glucopyranoside (AG5P), phenyl O-(alpha-D-glucopyranosyluronic acid)-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1-- --4)- alpha-D-glucopyranoside (CG5P), and phenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)- O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-a lph a-D- glucopyranoside (FG4P), were prepared to examine the active site of Taka-amylase A (TAA) [EC 3.2.1.1, Aspergillus oryzae]. Phenyl alpha-maltotetraoside (G4P) was predominantly hydrolyzed by TAA to maltose and phenyl alpha-maltoside (G2P). While G2P, phenyl alpha-glucoside (GP), and phenol were liberated from AG4P in the ratio of 7:63:30. G4P, phenyl alpha-maltotrioside (G3P), G2P, and GP were liberated from G5P in the ratio of 1:20:73:6, but AG5P was almost completely hydrolyzed to modified maltotriose and G2P. On the hydrolysis of CG4P and CG5P, no remarkable change was observed except for a decrease in the relative reaction rates compared with G4P and G5P, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Use of ion-exchange chromatography and high-performance liquid chromatography to prepare a substrate for differential assay of human pancreatic and salivary alpha-amylases in serum. JOURNAL OF CHROMATOGRAPHY 1987; 420:158-62. [PMID: 3499446 DOI: 10.1016/0378-4347(87)80167-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Differential rate assay of human pancreatic and salivary alpha-amylases in serum using two coupled enzymes. J Biochem 1986; 100:1353-8. [PMID: 3546280 DOI: 10.1093/oxfordjournals.jbchem.a121841] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
p-Nitrophenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha- D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-alpha-D-glucopyranoside (FG5P) is hydrolyzed by human pancreatic a-amylase (HPA) or salivary alpha-amylase (HSA) to O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-D-glucose (FG3) and p-nitrophenyl alpha-maltoside or to O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha- D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-D-glucose (FG4) and p-nitrophenyl alpha-glucoside. The use of alpha-D-glucosidase (maltase) [EC 3.2.1.20] of Saccharomyces carlsbergensis and oligo-1,6-glucosidase (isomaltase) [EC 3.2.1.10] of bakers' yeast as coupled enzymes differentiates between the two reactions, because alpha-D-glucosidase liberates p-nitrophenol from both p-nitrophenyl alpha-glucoside and p-nitrophenyl alpha-maltoside, but oligo-1,6-glucosidase liberates it only from p-nitrophenyl alpha-glucoside. HPA produces more FG4 and p-nitrophenyl alpha-glucoside than HSA. Taking advantage of the differences in the action of the two amylases and in the substrate specificity of the coupled enzymes, we have developed a new colorimetric differential rate assay of alpha-amylases in human serum.
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Measurement of cyclomaltodextrin glucanotransferase activity by high-performance liquid chromatography using a fluorogenic substrate. Anal Biochem 1986; 154:449-53. [PMID: 2942054 DOI: 10.1016/0003-2697(86)90013-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A mixture of p-nitrophenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranoside (FG5P) and p-nitrophenyl alpha-D-glucoside (GP) was incubated with cyclomaltodextrin glucanotransferase (CGTase) [EC 2.4.1.19]. Analysis of the digest by HPLC showed that the products were p-nitrophenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-alpha-D-glucopyranoside (FG4P) and p-nitrophenyl alpha-D-maltoside (G2P), and no other product could be detected. Based on the reaction, a sensitive method to assay for CGTase was developed.
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Inspection of active sites of human salivary alpha-amylase isozymes by means of non-reducing-end substituted maltooligosaccharides with 2-pyridylamino residue. J Biochem 1986; 99:1245-52. [PMID: 3486866 DOI: 10.1093/oxfordjournals.jbchem.a135588] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The modes of action of four alpha-amylase isozymes, which were purified from human saliva, on p-nitrophenyl alpha-maltopentaoside (G5P), maltohexaitol (G6R), and their 2-pyridylamino derivatives, p-nitrophenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha- D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-alpha-D-glucopyranoside (FG5P) and O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)- O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O- alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-D- glucitol (FG6R) were examined at various pH values. No differences in their modes of action on the substrates was found. Irrespective of which enzyme was used, the molar ratio of the hydrolysis products of G5P or G6R was almost constant at any pH examined. On the other hand, those of FG5P and FG6R varied with pH such that predominantly O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-D-glucose (FG3) was formed at high pH ranges, while the formation of O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)- O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-D-gl ucose (FG4) increased at lower pH. The result indicates that the binding mode of FG5P or FG6R to the active sites of the enzymes changed with pH; namely, interactions between the 2-pyridylamino residue of the substrates and some amino acid residue(s) located in the active sites were influenced by pH.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
The complete hydrolysis of a fluorogenic derivative of rho-nitrophenyl alpha-maltopentaoside, FG5P, by human salivary alpha-amylase, resulted in a 5-fold increase in fluorescence. This is due to disruption of the intramolecular quenching of the fluorescence of the 2-pyridylamino residue by the rho-nitrophenyl residue by separation of the two residues. This change of fluorescence accompanying the cleavage of the glucosidic bond was exploited to develop a fluorometric rate assay of alpha-amylase in human serum.
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Preparation of non-reducing-end substituted p-nitrophenyl alpha-maltopentaoside (FG5P) as a substrate for a coupled enzymatic assay for alpha-amylases. J Biochem 1985; 97:977-82. [PMID: 3161874 DOI: 10.1093/oxfordjournals.jbchem.a135174] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
p-Nitrophenyl O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha-D - glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-alpha-D-glucopyranoside, FG5P, was prepared, taking advantage of the action of Bacillus macerans cyclodextrin glucanotransferase on a mixture of O-6-deoxy-6-[(2-pyridyl)-amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha- D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-D-glucose and p-nitrophenyl alpha-glucoside. The maltopentaose derivative is resistant to alpha-glucosidase and is suitable as a substrate for the alpha-amylase assay coupled with alpha-glucosidase in which the activity of alpha-amylase is determined by measuring the amount of p-nitrophenol liberated by alpha-glucosidase from p-nitrophenyl alpha-glucoside and p-nitrophenyl alpha-maltoside produced by the action of alpha-amylase. This alpha-amylase assay method was applied for determination of alpha-amylases in human serum.
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Ion-exchange chromatography of fluorogenic derivatives of maltooligosaccharides for preparation of alpha-amylase substrates. JOURNAL OF CHROMATOGRAPHY 1984; 336:368-73. [PMID: 6442300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Differential assay of human pancreatic and salivary alpha-amylases in serum using a new fluorogenic substrate. Clin Chim Acta 1984; 138:197-203. [PMID: 6609786 DOI: 10.1016/0009-8981(84)90234-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The difference in the mode action of human pancreatic and salivary alpha-amylases on O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl-(1----4)-O-alpha-D - glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-D-glucitol FG6R), a fluorogenic derivative of maltohexaitol, was found. The products of the enzymatic hydrolysis were analyzed by high-performance liquid chromatography (HPLC) in 8 min. FG6R was hydrolyzed by these enzymes to O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D-glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-D-glucose (FG3) and maltotriitol, or O-6-deoxy-6-[(2-pyridyl)amino]-alpha-D- glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D- glucopyranosyl-(1----4)-D-glucose (FG4) and maltitol. Pancreatic alpha-amylase produced more FG4 than salivary alpha-amylase. Taking advantage of the differences in action of the two amylases, a differential alpha-amylase assay in serum was performed. The method is simple and rapid and can be used for routine clinical assays of alpha-amylases.
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