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Schlachter CR, McGee AC, Sitasuwan PN, Horvath GC, Karri NG, Lee LA, Tomashek JJ. Variants of glycosyl hydrolase family 2 β-glucuronidases have increased activity on recalcitrant substrates. Enzyme Microb Technol 2021; 145:109742. [PMID: 33750535 DOI: 10.1016/j.enzmictec.2020.109742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/18/2020] [Accepted: 12/23/2020] [Indexed: 11/29/2022]
Abstract
Glucuronidated drug metabolites can be quantified from urine samples by first hydrolyzing conjugates with β-glucuronidase (β-GUS) and then separating free drug molecules by liquid chromatography and mass spectrometry detection (LC-MS). To improve the activity and specificity of various β-GUS, we designed enzyme chimeras and generated site-saturation variants based on structural analyses, then screened them for improved activity on drug metabolites important to clinical and forensic drug-testing laboratories. Often, an increase of activity on one substrate of interest was countered by loss of activity against another, and there was no strong correlation of activity on standard β-glucuronidase substrates to activity on recalcitrant drug glucuronides. However, we discovered a chimera of two enzymes from different species of Aspergillus that displays a 27 % increase in activity on morphine-3-glucuronide than the parent proteins. Furthermore, mutations in the M-loop, which is a loop near the active site, resulted in numerous variants with dramatically increased rates of hydrolysis on drug glucuronides. Specifically, the M-loop variant Q451D/A452E of a β-GUS from Brachyspira pilosicoli has a 50-fold and 25-fold increase in activity on the recalcitrant substrates codeine-6-glucuronide and dihydrocodeine-6-glucuronide, respectively, compared to the parent enzyme.
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Affiliation(s)
- Caleb R Schlachter
- Integrated Micro-Chromatography Systems, 110 Centrum Drive, Irmo, SC, 29063, United States
| | - Amanda C McGee
- Integrated Micro-Chromatography Systems, 110 Centrum Drive, Irmo, SC, 29063, United States
| | - Pongkwan N Sitasuwan
- Integrated Micro-Chromatography Systems, 110 Centrum Drive, Irmo, SC, 29063, United States
| | - Gary C Horvath
- Integrated Micro-Chromatography Systems, 110 Centrum Drive, Irmo, SC, 29063, United States
| | - Nanda G Karri
- Integrated Micro-Chromatography Systems, 110 Centrum Drive, Irmo, SC, 29063, United States
| | - L Andrew Lee
- Integrated Micro-Chromatography Systems, 110 Centrum Drive, Irmo, SC, 29063, United States
| | - John J Tomashek
- Integrated Micro-Chromatography Systems, 110 Centrum Drive, Irmo, SC, 29063, United States.
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2
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Abstract
In this report, we detail Substrate Mediated Enzyme Prodrug Therapy (SMEPT) as a novel approach in drug delivery which relies on enzyme-functionalized cell culture substrates to achieve a localized conversion of benign prodrug(s) into active therapeutics with subsequent delivery to adhering cells or adjacent tissues. For proof-of-concept SMEPT, we use surface adhered micro-structured physical hydrogels based on poly(vinyl alcohol), β-glucuronidase enzyme and glucuronide prodrugs. We demonstrate enzymatic activity mediated by the assembled hydrogel samples and illustrate arms of control over rate of release of model fluorescent cargo. SMEPT was not impaired by adhering cells and afforded facile time - and dose - dependent uptake of the in situ generated fluorescent cargo by hepatic cells, HepG2. With the use of a glucuronide derivative of an anticancer drug, SN-38, SMEPT afforded a decrease in cell viability to a level similar to that achieved using parent drug. Finally, dose response was achieved using SMEPT and administration of judiciously chosen concentration of SN-38 glucuronide prodrug thus revealing external control over drug delivery using drug eluting surface. We believe that this highly adaptable concept will find use in diverse biomedical applications, specifically surface mediated drug delivery and tissue engineering.
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Affiliation(s)
| | - Alexander N. Zelikin
- Department of Chemistry, Aarhus University, Aarhus, Denmark
- iNano Interdisciplinary Nanoscience Centre, Aarhus University, Aarhus, Denmark
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3
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Kresse H, Glössl J. Glycosaminoglycan degradation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 60:217-311. [PMID: 3310531 DOI: 10.1002/9780470123065.ch4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- H Kresse
- Institute of Physiological Chemistry, University of Münster, Federal Republic of Germany
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4
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Nakamura T, Takagaki K, Majima M, Kimura S, Kubo K, Endoss M. A new type of exo-beta-glucuronidase acting only on non-sulfated glycosaminoglycans. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39371-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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5
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de Groen PC, LeSage GD, Tietz PS, LaRusso NF. Purification and immunological quantification of rat liver lysosomal glycosidases. Biochem J 1989; 264:115-23. [PMID: 2513804 PMCID: PMC1133554 DOI: 10.1042/bj2640115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Although lysosomal enzyme activities are known to vary in response to numerous physiological and pharmacological stimuli, the relationship between lysosomal enzyme activity and enzyme concentration has not been systematically studied. Therefore we developed radioimmunoassays for two lysosomal glycosidases in order to determine lysosomal enzyme concentration. beta-Galactosidase and beta-glucuronidase were purified from rat liver 2780-fold and 1280-fold respectively, by using differential centrifugation, affinity chromatography, ion-exchange chromatography and molecular-sieve chromatography. Polyclonal antibodies to these enzymes were raised in rabbits, and two radioimmunoassays were established. Antibody specificity was shown by: (i) selective immunoprecipitation of enzyme activity; (ii) identical bands of purified enzyme on SDS/polyacrylamide-gel electrophoresis and immunoelectrophoresis; (iii) single immunoreactive peaks in molecular-sieve chromatography experiments. Sensitivities of the assays were such that 15 ng of beta-galactosidase and 45 ng of beta-glucuronidase decreased the ratio of bound to free radiolabel by 50%; minimal detectable amounts of immunoreactive enzymes were 2 ng and 10 ng respectively. The assays were initially used to assess the effects of physiological perturbations (i.e. fasting and age) on enzyme concentrations in rat liver; these experiments showed that changes in enzyme concentrations do not always correlate with changes in enzyme activities. This represents the first report of radioimmunoassays for lysosomal glycosidases. The results suggest that these radioimmunoassays provide useful technology for the study of regulatory control mechanisms of the concentrations of lysosomal glycosidases in mammalian tissues.
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Affiliation(s)
- P C de Groen
- Gastroenterology Research Unit, Mayo Medical School, MN 55905
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6
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Nakamura T, Takagaki K, Majima M, Endo M. Demonstration of N-acetylchondrosine-degrading beta-glucuronidase in rabbit liver. FEBS Lett 1988; 234:91-4. [PMID: 3391274 DOI: 10.1016/0014-5793(88)81310-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
N-Acetylchondrosine was incubated at pH 4.0 with a rabbit-liver crude enzyme extract. Gel filtration of the reaction products on Sephadex G-15 revealed the presence of monosaccharide liberated from the disaccharide. The monosaccharide fraction was analyzed by gas-liquid chromatography, and identified as a mixture of glucuronic acid and N-acetylgalactosamine. These results indicate the presence of beta-glucuronidase, which degrades N-acetylchondrosine, in rabbit liver. The discovery of the presence of this enzyme may help to establish the complete degradation process of chondroitin sulfates.
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Affiliation(s)
- T Nakamura
- Department of Biochemistry, Hirosaki University School of Medicine, Japan
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7
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Takagaki K, Nakamura T, Majima M, Endo M. Isolation and characterization of a chondroitin sulfate-degrading endo-beta-glucuronidase from rabbit liver. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68595-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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8
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Abstract
beta-glucuronidase was purified by affinity chromatography on thiophenyl-glucuronide coupled to Sepharose. The enzyme was more than 95% pure. This enzyme is a tetramer composed of identical 74 kDa monomers. The amino-terminal sequence determined was: NH2-Met-Leu-Arg-Pro-Val.
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9
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Study of kinetics of enzymatic hydrolysis of ammonium glycyrrhizate. Pharm Chem J 1985. [DOI: 10.1007/bf00766849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Covell AM, Worwood M. Turnover and tissue uptake of rabbit ferritin from rabbit plasma. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1984; 77:829-34. [PMID: 6734152 DOI: 10.1016/0305-0491(84)90319-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Using a two-site immunoradiometric assay for rabbit liver ferritin normal NZW rabbits were found to have very low plasma ferritin concentrations (less than 4 micrograms/l). Purified preparations of rabbit liver and kidney ferritin were labelled with 125I and injected into rabbits. Clearance from plasma was extremely rapid with an initial half-life of 1-2 min as measured by immunoprecipitation of labelled ferritin. The rate of clearance was unaffected by the labelling procedure and by the method of ferritin purification. Autoradiography and organ uptake studies showed that 125I-rabbit liver ferritin was removed mainly by liver reticuloendothelial cells, although on a weight basis, spleen had the greatest radioactivity. These studies indicate that rabbit ferritin released into the circulation is promptly cleared by the RES.
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12
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Schwartz LB, Austen KF. Purification and characterization of a lysosomal form and a variant form of beta-glucuronidase from the rat basophil leukaemia tumour. Biochem J 1981; 193:663-70. [PMID: 7305955 PMCID: PMC1162653 DOI: 10.1042/bj1930663] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Two isoenzyme of beta-glucuronidase from a rat basophil leukaemia tumour were co-purified 4067-fold by (NH4)2SO4 precipitation and sequential chromatography on concanavalin A--Sepharose, Sephadex G-200, DEAE-cellulose, CM-cellulose and phosphocellulose. The purity of the mixture was established by the coincidence of the peaks of enzyme activity and protein at a molecular weight of 300 000 on Bio-Gel P-300, the presence of only two protein bands, both of them enzymically active, in polyacrylamide gels after electrophoresis under non-denaturing conditions, and the presence of a single subunit species, of mol.wt. 75 000, after electrophoresis in polyacrylamide gels under a denaturing conditioning. The major isoenzyme co-migrated with the L form from rat liver during electrophoresis in alkaline polyacrylamide gels, whereas the minor isoenzyme migrated more rapidly than either the lysosomal form or the rat liver microsomal form and was designated the tumour (T) isoenzyme. A mixture of the purified isoenzymes from two preparations had an average specific activity of 1389 units/mg for phenolphthalein beta-D-glycopyranosiduronic acid. The L and T isoenzymes, which had pI5.9 and 5.7 respectively, could be obtained free of cross-contamination by isoelectric focusing and had similar specific activities. Although the T isoenzyme could be a catabolic product of the M or the L form, it could also be a unique tumour product, because it was not detected in extracts of normal rat tissues.
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13
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Miyagawa T, Eguchi Y. Acid deoxyribonuclease, acid phosphodiesterase and acid phosphatase of new born rat epidermis (skin): multiple forms and glycoprotein nature. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C: COMPARATIVE PHARMACOLOGY 1981; 69C:39-43. [PMID: 6113090 DOI: 10.1016/0306-4492(81)90099-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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14
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15
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Gowers HM, Breuer H. Purification and properties of a beta-glucuronidase from pig kidney. JOURNAL OF STEROID BIOCHEMISTRY 1980; 13:1021-7. [PMID: 7421244 DOI: 10.1016/0022-4731(80)90132-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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16
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17
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Skilleter DN, Price RJ. The role of lysosomes in the hepatic accumulation and release of beryllium. Biochem Pharmacol 1979; 28:3595-9. [PMID: 533561 DOI: 10.1016/0006-2952(79)90405-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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18
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Biosynthesis of two lysosomal enzymes in macrophages. Evidence for a precursor of beta-galactosidase. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86648-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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19
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The topological orientation of N,N'-diacetylchitobiosylpyrophosphoryldolichol in artificial and natural membranes. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86836-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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20
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Glaser JH, Conrad HE. Chick embryo liver beta-glucuronidase. Comparison of activity on natural and artificial substrates. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(18)50409-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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21
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Diez T, Cabezas JA. Properties of two molecular forms of beta-glucuronidase from the mollusc Littorina littorea L. EUROPEAN JOURNAL OF BIOCHEMISTRY 1979; 93:301-11. [PMID: 428383 DOI: 10.1111/j.1432-1033.1979.tb12824.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The occurrence of the two molecular forms, I and II, in the beta-glucuronidase of the liver (hepatopancreas) from the marine mollusc Littorina littorea L. has been demonstrated for the first time. The two forms have been purified 355-fold and 1262-fold, respectively. Form I and II of beta-glucuronidase behave differently on DEAE-cellulose chromatography, polyacrylamide gel disc electrophoresis, isoelectric focusing (pH 5.5 and 4.2, respectively), optimum pH (4.4 and 3.4--4.1, respectively), thermal stability, Km (1.2 mM and 0.5 mM with p-nitrophenyl beta-D-glucuronide, 0.3 mM and 0.15 mM with phenolphthalein beta-D-glucuronide as substrates for form I and II, respectively) and V. Their molecular weight, estimated by gel filtration through Sephadex G-200, was about 250000 for both forms. Several subunits were separated by polyacrylamide gel electrophoresis in presence of sodium dodecyl sulphate. This beta-glucuronidase is a glycoprotein, but sialic acid(s) were not detected. The enzyme was very active on synthetic substrates and also on hexasaccharides and tetrasaccharides containing glucuronic acid residues with beta 1 leads to 3 linkages; it had practially no activity on certain glycosaminoglycans. Hg2+ and glucaro-1,4-lactone were very effective inhibitors of this enzyme; the latter by a competitive mechanism.
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22
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Périn JP, Jollès P. Characterization of human leukocyte beta-glucuronidase. Biochimie 1978; 60:543-6. [PMID: 698292 DOI: 10.1016/s0300-9084(78)80873-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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24
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25
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26
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Swank RT, Paigen K, Davey R, Chapman V, Labarca C, Watson G, Ganschow R, Brandt EJ, Novak E. Genetic regulation of mammalian glucuronidase. RECENT PROGRESS IN HORMONE RESEARCH 1978; 34:401-36. [PMID: 366684 DOI: 10.1016/b978-0-12-571134-0.50015-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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27
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Labarca C, Paigen K. MRNA-directed synthesis of catalytically active mouse beta-glucuronidase in Xenopus oocytes. Proc Natl Acad Sci U S A 1977; 74:4462-5. [PMID: 270691 PMCID: PMC431963 DOI: 10.1073/pnas.74.10.4462] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Catalytically active mouse beta-glucuronidase (beta-D-glucuronide glucuronosohydrolase, EC 3.2.1.31) is formed when Xenopus oocytes are injected with mouse RNA enriched for poly(A)-containing mRNA sequences. With the RNA from androgen-induced kidneys, the efficiency of translation is comparable to that of endogenous Xenopus messenger, and the fidelity of translation is high. Detection of glucuronidase messenger by formation of a catalytically active product is several orders of magnitude more sensitive than detection by incorporation of isotopically labeled amino acids. As well as providing a sensitive technique for examining the regulation of gene expression, the system makes available an opportunity to study the regulation of post-translational polypeptide processing of a lysosomal enzyme.
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28
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Opheim DJ, Touster O. The purification and characterization of rat liver lysosomal alpha-L-fucosidase. J Biol Chem 1977. [DOI: 10.1016/s0021-9258(17)32780-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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29
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Himeno Mnishimura Y, Tsuji H, Kato K. Purification and characterization of microsomal and lysosomal beta-glucuronidase from rat liver by use of immunoaffinity chromatography. EUROPEAN JOURNAL OF BIOCHEMISTRY 1976; 70:349-59. [PMID: 64358 DOI: 10.1111/j.1432-1033.1976.tb11024.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rat liver beta-glucuronidase (EC 3.2.1.31), both from microsomal and lysosomal fractions, were purified about 9500-fold over the homogenate with high yield using affinity chromatography prepared by coupling purified specific immunoglobulin G against rat preputial gland beta-glucuronidase to Sepharose 2B and isoelectric focusing. The purified enzymes appeared homogeneous on electrophoresis in polyacrylamide gel and had a molecular weight of approximately 310000. In dodecylsulfate polyacrylamide gel electrophoresis, the microsomal beta-glucuronidase showed a single band corresponding to a molecular weight of 79000, while the lysosomal beta-glucuronidase had three distinct bands which consisted of one major and two minor bands corresponding to molecular weight of 79000, 74000, and 70000, respectively. A broad pH activity curve with a single optimum at pH 4.4 was observed in both the microsomal and the lysosomal beta-glucuronidases. Immunological gel diffusion technique with rabbit antiserum against rat liver lysosomal beta-glucuronidase revealed that both enzymes had the same or quite similar antigenic determinants.
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30
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Owens JW, Stahl P. Purification and characterization of rat liver microsomal beta-glucuronidase. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 438:474-86. [PMID: 8108 DOI: 10.1016/0005-2744(76)90263-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Beta-Glucuronidase (EC 3.2.1.31) has been isolated from rat-liver microsomes by a novel chromatographic method employing antibody to rat preputial gland beta-glucuronidase coupled to Sepharose. The purified enzyme, homogeneous by several methods, was purified some 1700-fold. The microsomal beta-glucuronidase has been characterized with respect to catalysis, stability, and molecular weight. The purified enzyme is a tetramer of 290 000 daltons. Comparative studies with lysosomal beta-glucuronidase indicate that while these two enzymes are electrophoretically distinct, they are catalytically and immunologically identical and have indistinguishable molecular dimensions. The results suggest that microsomal and lysosomal beta-glucuronidase are charge isomers.
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31
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Messer M, Dean RT. Immunochemical relationship between alpha-amylases of rat liver, serum, pancreas and parotid gland. Biochem J 1975; 151:17-22. [PMID: 55120 PMCID: PMC1172320 DOI: 10.1042/bj1510017] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. Rabbit antisera to purified rat parotid alpha-amylase were prepared. 2. The relationships between rat parotid-gland, pancreatic, serum and liver amylase were investigated by using the antisera in immunodiffusion, immunoelectrophoresis and immunoinhibition experiments. 3. Serum and liver amylase were identical, and very similar to parotid-gland amylase; pancreatic amylase was, however, quite distinct, and showed only some of the determinants present on parotid-gland amylase. 4. The data strengthen the suggestion that the liver is the main source of serum amylase.
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32
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Tulsiani DR, Keller RK, Touster O. The preparation and chemical composition of the multiple forms of beta-glucuronidase from the female rat preputial gland. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41369-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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33
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Lin CW, Orcutt ML, Fishman WH. Purification and characterization of mouse kidney beta-glucuronidase. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41364-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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34
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Dean RT, Messer M. Evidence against the occurrence of artifacts due to carrier ampholyte-protein binding during isoelectric focusing. J Chromatogr A 1975; 105:353-8. [PMID: 239009 DOI: 10.1016/s0021-9673(01)82265-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The formation of irreversible complexes between carrier ampholyte components and proteins was investigated by gel filtration of mixtures of proteins and radioactively labelled ampholytes. Experiments were performed both with purified proteins (albumin, ferritin, beta-glucuronidase) and with a complex mixture of proteins (serum); in no case was binding of ampholytes to proteins detected. Thus the results argue against the occurrence in isoelectric focusing of proteins of artifacts due to such complex formation.
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35
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Abstract
1. The subcellular distribution of beta-glucuronidase and other hydrolases in rabbit liver was investigated. beta-Glucuronidase was found in both microsomal and lysosomal fractions. 2. Multiple forms of beta-glucuronidase were present in extracts of microsomal and lysosomal fractions. All forms were common to both fractions. 3. A specific antiserum against beta-glucuronidase was raised, and characterized by immunoprecipitation and affinity-chromatography procedures. 4. The immunological identity of the multiple forms in the pure beta-glucuronidase preparation, and the immunological identity of the beta-glucuronidase complement of lysosomal extracts with that of microsomal extracts, were demonstrated by means of the antiserum. The presence of inactive enzyme in various enzyme preparations was shown.
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