1
|
Balasundaram A, Ramireddy S, S UK, D TK, Tayubi IA, Zayed H, C GPD. A new horizon in the phosphorylated sites of AGA: the structural impact of C163S mutation in aspartylglucosaminuria through molecular dynamics simulation. J Biomol Struct Dyn 2024; 42:4313-4324. [PMID: 37334725 DOI: 10.1080/07391102.2023.2220798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 05/28/2023] [Indexed: 06/20/2023]
Abstract
Aspartylglucosaminuria (AGU) is a lysosomal storage disorder caused by insufficient aspartylglucosaminidase (AGA) activity leading to chronic neurodegeneration. We utilized the PhosphoSitePlus tool to identify the AGA protein's phosphorylation sites. The phosphorylation was induced on the specific residue of the three-dimensional AGA protein, and the structural changes upon phosphorylation were studied via molecular dynamics simulation. Furthermore, the structural behaviour of C163S mutation and C163S mutation with adjacent phosphorylation was investigated. We have examined the structural impact of phosphorylated forms and C163S mutation in AGA. Molecular dynamics simulations (200 ns) exposed patterns of deviation, fluctuation, and change in compactness of Y178 phosphorylated AGA protein (Y178-p), T215 phosphorylated AGA protein (T215-p), T324 phosphorylated AGA protein (T324-p), C163S mutant AGA protein (C163S), and C163S mutation with Y178 phosphorylated AGA protein (C163S-Y178-p). Y178-p, T215-p, and C163S mutation demonstrated an increase in intramolecular hydrogen bonds, leading to greater compactness of the AGA forms. Principle component analysis (PCA) and Gibbs free energy of the phosphorylated/C163S mutation structures exhibit transition in motion/orientation than Wild type (WT). T215-p may be more dominant among these than the other studied phosphorylated forms. It might contribute to hydrolyzing L-asparagine functioning as an asparaginase, thereby regulating neurotransmitter activity. This study revealed structural insights into the phosphorylation of Y178, T215, and T324 in AGA protein. Additionally, it exposed the structural changes of the C163S mutation and C163S-Y178-p of AGA protein. This research will shed light on a better understanding of AGA's phosphorylated mechanism.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Ambritha Balasundaram
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Sriroopreddy Ramireddy
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Udhaya Kumar S
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Thirumal Kumar D
- Faculty of Allied Health Sciences, Meenakshi Academy of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Iftikhar Aslam Tayubi
- Department of Computer Science, Faculty of Computing and Information Technology, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Hatem Zayed
- Department of Biomedical Sciences College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | - George Priya Doss C
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| |
Collapse
|
2
|
Coulette Q, Lemauf S, Colinet D, Prévost G, Anselme C, Poirié M, Gatti JL. Biochemical characterization and comparison of aspartylglucosaminidases secreted in venom of the parasitoid wasps Asobara tabida and Leptopilina heterotoma. PLoS One 2017; 12:e0181940. [PMID: 28742131 PMCID: PMC5524358 DOI: 10.1371/journal.pone.0181940] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/10/2017] [Indexed: 11/18/2022] Open
Abstract
Aspartylglucosaminidase (AGA) is a low-abundance intracellular enzyme that plays a key role in the last stage of glycoproteins degradation, and whose deficiency leads to human aspartylglucosaminuria, a lysosomal storage disease. Surprisingly, high amounts of AGA-like proteins are secreted in the venom of two phylogenetically distant hymenopteran parasitoid wasp species, Asobara tabida (Braconidae) and Leptopilina heterotoma (Cynipidae). These venom AGAs have a similar domain organization as mammalian AGAs. They share with them key residues for autocatalysis and activity, and the mature α- and β-subunits also form an (αβ)2 structure in solution. Interestingly, only one of these AGAs subunits (α for AtAGA and β for LhAGA) is glycosylated instead of the two subunits for lysosomal human AGA (hAGA), and these glycosylations are partially resistant to PGNase F treatment. The two venom AGAs are secreted as fully activated enzymes, they have a similar aspartylglucosaminidase activity and are both also efficient asparaginases. Once AGAs are injected into the larvae of the Drosophila melanogaster host, the asparaginase activity may play a role in modulating their physiology. Altogether, our data provide new elements for a better understanding of the secretion and the role of venom AGAs as virulence factors in the parasitoid wasps' success.
Collapse
Affiliation(s)
- Quentin Coulette
- Unité “Ecologie et Dynamique des Systèmes Anthropisés” (EDYSAN, FRE 3498 CNRS-UPJV), Université de Picardie Jules Verne, Amiens, France
| | - Séverine Lemauf
- Université Côte d’Azur, INRA, CNRS, ISA, Sophia Antipolis, France
| | | | - Geneviève Prévost
- Unité “Ecologie et Dynamique des Systèmes Anthropisés” (EDYSAN, FRE 3498 CNRS-UPJV), Université de Picardie Jules Verne, Amiens, France
| | - Caroline Anselme
- Unité “Ecologie et Dynamique des Systèmes Anthropisés” (EDYSAN, FRE 3498 CNRS-UPJV), Université de Picardie Jules Verne, Amiens, France
| | - Marylène Poirié
- Université Côte d’Azur, INRA, CNRS, ISA, Sophia Antipolis, France
| | - Jean-Luc Gatti
- Université Côte d’Azur, INRA, CNRS, ISA, Sophia Antipolis, France
| |
Collapse
|
3
|
Pande S, Lakshminarasimhan D, Guo HC. Crystal structure of a mutant glycosylasparaginase shedding light on aspartylglycosaminuria-causing mechanism as well as on hydrolysis of non-chitobiose substrate. Mol Genet Metab 2017; 121:150-156. [PMID: 28457719 PMCID: PMC5504686 DOI: 10.1016/j.ymgme.2017.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/18/2017] [Accepted: 04/18/2017] [Indexed: 10/19/2022]
Abstract
Glycosylasparaginase (GA) is an amidase that cleaves Asn-linked glycoproteins in lysosomes. Deficiency of this enzyme causes accumulation of glycoasparagines in lysosomes of cells, resulting in a genetic condition called aspartylglycosaminuria (AGU). To better understand the mechanism of a disease-causing mutation with a single residue change from a glycine to an aspartic acid, we generated a model mutant enzyme at the corresponding position (named G172D mutant). Here we report a 1.8Å resolution crystal structure of mature G172D mutant and analyzed the reason behind its low hydrolase activity. Comparison of mature G172D and wildtype GA models reveals that the presence of Asp 172 near the catalytic site affects substrate catabolism in mature G172D, making it less efficient in substrate processing. Also recent studies suggest that GA is capable of processing substrates that lack a chitobiose (Glycan, N-acetylchiobios, NAcGlc) moiety, by its exo-hydrolase activity. The mechanism for this type of catalysis is not yet clear. l-Aspartic acid β-hydroxamate (β-AHA) is a non-chitobiose substrate that is known to interact with GA. To study the underlying mechanism of non-chitobiose substrate processing, we built a GA-β-AHA complex structure by comparing to a previously published G172D mutant precursor in complex with a β-AHA molecule. A hydrolysis mechanism of β-AHA by GA is proposed based on this complex model.
Collapse
Affiliation(s)
- Suchita Pande
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
| | - Damodharan Lakshminarasimhan
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
| | - Hwai-Chen Guo
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA.
| |
Collapse
|
4
|
Abstract
Aspartylglucosaminuria (AGU), a recessively inherited lysosomal storage disease, is the most common disorder of glycoprotein degradation with a high prevalence in the Finnish population. It is a lifelong condition affecting on the patient's appearance, cognition, adaptive skills, physical growth, personality, body structure, and health. An infantile growth spurt and development of macrocephalia associated to hernias and respiratory infections are the key signs to an early identification of AGU. Progressive intellectual and physical disability is the main symptom leading to death usually before the age of 50 years.The disease is caused by the deficient activity of the lysosomal enzyme glycosylasparaginase (aspartylglucosaminidase, AGA), which leads to a disorder in the degradation of glycoasparagines - aspartylglucosamine or other glycoconjugates with an aspartylglucosamine moiety at their reducing end - and accumulation of these undegraded glycoasparagines in tissues and body fluids. A single nucleotide change in the AGA gene resulting in a cysteine to serine substitution (C163S) in the AGA enzyme protein causes the deficiency of the glycosylasparaginase activity in the Finnish population. Homozygosity for the single nucleotide change causing the C163S mutation is responsible for 98% of the AGU cases in Finland simplifying the carrier detection and prenatal diagnosis of the disorder in the Finnish population. A mouse strain, which completely lacks the Aga activity has been generated through targeted disruption of the Aga gene in embryonic stem cells. These Aga-deficient mice share most of the clinical, histopathologic and biochemical characteristics of human AGU disease. Treatment of AGU mice with recombinant AGA resulted in rapid correction of the pathophysiologic characteristics of AGU in non-neuronal tissues of the animals. The accumulation of aspartylglucosamine was reduced by up to 40% in the brain tissue of the animals depending on the age of the animals and the therapeutic protocol. Enzyme replacement trials on human AGU patients have not been reported so far. Allogenic stem cell transplantation has not proved effective in curing AGU.
Collapse
Affiliation(s)
- Maria Arvio
- Päijät-Häme Social Welfare & Healthcare Joint Municipal Board, Lahti, Finland. .,KTO, The Special Welfare District of Southwestern Finland, Paimio, Finland. .,PEDEGO Research Unit, Oulu University Hospital, Finland, Oulu, Finland.
| | - Ilkka Mononen
- Newborn Screening Center Finland, Saske, Turku University Central Hospital, Turku, Finland.,The Joint Clinical Chemistry Laboratory at Turku University Hospital, Turku, Finland.,Department of Clinical Chemistry, University of Turku, PO Box 52, FIN-20521, Turku, Finland
| |
Collapse
|
5
|
Kelo E, Noronkoski T, Mononen I. Depletion of L-asparagine supply and apoptosis of leukemia cells induced by human glycosylasparaginase. Leukemia 2009; 23:1167-71. [DOI: 10.1038/leu.2008.387] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
6
|
Borek D, Michalska K, Brzezinski K, Kisiel A, Podkowinski J, Bonthron DT, Krowarsch D, Otlewski J, Jaskolski M. Expression, purification and catalytic activity of Lupinus luteus asparagine β-amidohydrolase and its Escherichia coli homolog. ACTA ACUST UNITED AC 2004; 271:3215-26. [PMID: 15265041 DOI: 10.1111/j.1432-1033.2004.04254.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We describe the expression, purification, and biochemical characterization of two homologous enzymes, with amidohydrolase activities, of plant (Lupinus luteus potassium-independent asparaginase, LlA) and bacterial (Escherichia coli, ybiK/spt/iaaA gene product, EcAIII) origin. Both enzymes were expressed in E. coli cells, with (LlA) or without (EcAIII) a His-tag sequence. The proteins were purified, yielding 6 or 30 mg.L(-1) of culture, respectively. The enzymes are heat-stable up to 60 degrees C and show both isoaspartyl dipeptidase and l-asparaginase activities. Kinetic parameters for both enzymatic reactions have been determined, showing that the isoaspartyl peptidase activity is the dominating one. Despite sequence similarity to aspartylglucosaminidases, no aspartylglucosaminidase activity could be detected. Phylogenetic analysis demonstrated the relationship of these proteins to other asparaginases and aspartylglucosaminidases and suggested their classification as N-terminal nucleophile hydrolases. This is consistent with the observed autocatalytic breakdown of the immature proteins into two subunits, with liberation of an N-terminal threonine as a potential catalytic residue.
Collapse
Affiliation(s)
- Dominika Borek
- Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, Poland
| | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Kelo E, Noronkoski T, Stoineva IB, Petkov DD, Mononen I. β-Aspartylpeptides as substrates ofL-asparaginases fromEscherichia coliandErwinia chrysanthemi. FEBS Lett 2002; 528:130-2. [PMID: 12297292 DOI: 10.1016/s0014-5793(02)03273-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
L-Asparaginase is known to catalyze the hydrolysis of L-asparagine to L-aspartic and ammonia, but little is known about its action on peptides. When we incubated L-asparaginases purified either from Escherichia coli or Erwinia chrysanthemi - commonly used as chemotherapeutic agents because of their antitumour activity - with eight small beta-aspartylpeptides such as beta-aspartylserineamide, beta-aspartylalanineamide, beta-aspartylglycineamide and beta-aspartylglycine, we found that both L-asparaginases could catalyze the hydrolysis of five of them yielding L-aspartic acid and amino acids or peptides. Our data show that L-asparaginases can hydrolyze beta-aspartylpeptides and suggest that L-asparaginase therapy may affect the metabolism of beta-aspartylpeptides present in human body.
Collapse
Affiliation(s)
- Eira Kelo
- Department of Clinical Chemistry, Kuopio University Hospital, Finland.
| | | | | | | | | |
Collapse
|
8
|
Bush LA, Herr JC, Wolkowicz M, Sherman NE, Shore A, Flickinger CJ. A novel asparaginase-like protein is a sperm autoantigen in rats. Mol Reprod Dev 2002; 62:233-47. [PMID: 11984834 DOI: 10.1002/mrd.10092] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A novel asparaginase-like protein (ALP) of spermatozoa was cloned from rat and human testis cDNA libraries on the basis of reactivity with antibodies produced after vasectomy. Although obstruction of the male reproductive tract is known to cause an immunologic response, few of the sperm antigens responsible for the generation of autoantibodies have been characterized. We are identifying proteins of interest by coring autoantigenic protein spots from two-dimensional (2-D) gels of rat sperm extracts and microsequencing them by mass spectrometry. The peptide sequences from ALP, a 28 kDa, pI 5.7 protein, matched to a single partial length rat EST. These peptide sequences were used to clone a cDNA encoding a novel 333 amino acid open reading frame. The new protein had a similarity to portions of L-asparaginases of plants (43%) and to glycosylasparaginases in animal cells (32%). Human ALP cDNA was subsequently cloned. It showed 77% identity to the rat ALP sequence and the gene, ASRGL1 (asparaginase-like 1), mapped to chromosome locus 11q12.3. Purified recombinant rat ALP (rALP), expressed in E. coli, was used to raise polyclonal antiserum in guinea pigs. Two observations verified that the correct protein had been cloned: 1) the anti-rALP antibody reacted with both rALP and rat sperm; and 2) post-vasectomy sera bound rALP. Anti-rALP antibody stained the midpiece of rat and human sperm coincident with staining by MitoTracker Green FM, suggesting that ALP is associated with the mitochondria. Northern analysis revealed that rat ALP message was abundantly expressed in the testis but was also present in heart, brain, liver, skeletal muscle, and kidney.
Collapse
Affiliation(s)
- Leigh Ann Bush
- Department of Cell Biology and the Center for Recombinant Gamete Contraceptive Vaccinogens, University of Virginia, Charlottesville 22908-0732, USA
| | | | | | | | | | | |
Collapse
|
9
|
Hejazi M, Piotukh K, Mattow J, Deutzmann R, Volkmer-Engert R, Lockau W. Isoaspartyl dipeptidase activity of plant-type asparaginases. Biochem J 2002; 364:129-36. [PMID: 11988085 PMCID: PMC1222554 DOI: 10.1042/bj3640129] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recombinant plant-type asparaginases from the cyanobacteria Synechocystis sp. PCC (Pasteur culture collection) 6803 and Anabaena sp. PCC 7120, from Escherichia coli and from the plant Arabidopsis thaliana were expressed in E. coli with either an N-terminal or a C-terminal His tag, and purified. Although each of the four enzymes is encoded by a single gene, their mature forms consist of two protein subunits that are generated by autoproteolytic cleavage of the primary translation products at the Gly-Thr bond within the sequence GTI/VG. The enzymes not only deamidated asparagine but also hydrolysed a range of isoaspartyl dipeptides. As various isoaspartyl peptides are known to arise from proteolytic degradation of post-translationally altered proteins containing isoaspartyl residues, and from depolymerization of the cyanobacterial reserve polymer multi-L-arginyl-poly-L-aspartic acid (cyanophycin), plant-type asparaginases may not only function in asparagine catabolism but also in the final steps of protein and cyanophycin degradation. The properties of these enzymes are compared with those of the sequence-related glycosylasparaginases.
Collapse
Affiliation(s)
- Mahdi Hejazi
- Institut für Biologie, Humboldt-Universität zu Berlin, Chausseestr. 117, D-10115 Berlin, Germany
| | | | | | | | | | | |
Collapse
|
10
|
Risley JM, Huang DH, Kaylor JJ, Malik JJ, Xia YQ. Glycosylasparaginase inhibition studies: competitive inhibitors, transition state mimics, noncompetitive inhibitors. JOURNAL OF ENZYME INHIBITION 2002; 16:269-74. [PMID: 11697047 DOI: 10.1080/14756360109162375] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Glycosylasparaginase catalyzes the hydrolysis of the N-glycosylic bond between asparagine and N-acetylglucosamine in the catabolism of N-linked glycoproteins. Previously only three competitive inhibitors, one noncompetitive inhibitor, and one irreversible inhibitor of glycosylasparaginase activity had been reported. Using human glycosylasparaginase from human amniotic fluid, L-aspartic acid and four of its analogues, where the alpha-amino group was substituted with a chloro, bromo, methyl or hydrogen, were competitive inhibitors having Ki values between 0.6-7.7 mM. These results provide supporting evidence for a proposed intramolecular autoproteolytic activation reaction. A proposed phosphono transition state mimic and a sulfo transition state mimic were competitive inhibitors with Ki values 0.9 mM and 1.4 mM, respectively. These results support a mechanism for the enzyme-catalyzed reaction involving formation of a tetrahedral high-energy intermediate. Three analogues of the natural substrate were noncompetitive inhibitors with Ki values between 0.56-0.75 mM, indicating the presence of a second binding site that may recognize (substituted)acetamido groups.
Collapse
Affiliation(s)
- J M Risley
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
| | | | | | | | | |
Collapse
|
11
|
Risley JM, Huang DH, Kaylor JJ, Malik JJ, Xia YQ, York WM. Glycosylasparaginase activity requires the alpha-carboxyl group, but not the alpha-amino group, on N(4)-(2-Acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine. Arch Biochem Biophys 2001; 391:165-70. [PMID: 11437347 DOI: 10.1006/abbi.2001.2416] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glycosylasparaginase catalyzes the hydrolysis of the N-glycosylic bond in N(4)-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine in the catabolism of N-linked oligosaccharides. A deficiency, or absence, of enzyme activity gives rise to aspartylglycosaminuria, the most common disorder of glycoprotein metabolism. The enzyme catalyzes the hydrolysis of a variety of asparagine and aspartyl compounds containing a free alpha-carboxyl group and a free alpha-amino group; computational studies suggest that the alpha-amino group actively participates in the catalytic mechanism. In order to study the importance of the alpha-carboxyl group and the alpha-amino group on the natural substrate to the reaction catalyzed by the enzyme, 14 analogues of the natural substrate were studied where the structure of the aspartyl group of the substrate was changed. The incremental binding energy (DeltaDeltaGb) for those analogues that were substrates was calculated. The results show that the alpha-amino group may be substituted with a group of comparable size, for the alpha-amino group contributes little, if any, to the transition state binding energy of the natural substrate. The alpha-amino group position acts as an "anchor" in the binding site for the substrate. On the other hand, the alpha-carboxyl group is necessary for enzyme activity; removal of the alpha-carboxyl group or changing it to an alpha-carboxamide group results in no hydrolysis reaction. Also, N-acetyl-D-glucosamine is not sufficient for binding to the active site for efficient hydrolysis by the enzyme. These results provide supporting evidence for a proposed intramolecular autoproteolytic activation reaction for the enzyme. However, the results raise a question as to an important role for the alpha-amino group in the catalytic mechanism as indicated in computational studies.
Collapse
Affiliation(s)
- J M Risley
- Department of Chemistry, The University of North Carolina at Charlotte, Charlotte, North Carolina 28223, USA.
| | | | | | | | | | | |
Collapse
|
12
|
Ylikangas P, Mononen I. A fluorometric assay for L-asparaginase activity and monitoring of L-asparaginase therapy. Anal Biochem 2000; 280:42-5. [PMID: 10805519 DOI: 10.1006/abio.2000.4500] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The antineoplastic enzyme L-asparaginase is commonly used for the induction of remission in acute lymphoblastic leukemia (ALL). There is no simple method available for measuring the activity of this highly toxic drug. We incubated L-asparaginase from Erwinia chrysanthemi with L-aspartic acid beta-(7-amido-4-methylcoumarin) and measured the release of 7-amino-4-methylcoumarin fluorometrically for 30-300 min. The rate of the hydrolysis of the substrate was linear over a 50-fold range of the concentration of the enzyme. With increasing substrate concentration, the enzyme showed a saturable kinetic pattern with V(max) of 0.547 (SD 0.059) microM/min/mg of enzyme (n = 3) and Km of 0.302 (SD 0.095) mM (n = 3). This assay enables rapid analysis of L-asparaginase activity in biological samples and it can be used, for example, for monitoring of L-asparaginase activity in serum of ALL patients during their L-asparaginase therapy.
Collapse
Affiliation(s)
- P Ylikangas
- Department of Clinical Chemistry, Päijät-Häme Central Hospital, Lahti, Finland
| | | |
Collapse
|
13
|
Noronkoski T, Stoineva IB, Ivanov IP, Petkov DD, Mononen I. Glycosylasparaginase-catalyzed synthesis and hydrolysis of beta-aspartyl peptides. J Biol Chem 1998; 273:26295-7. [PMID: 9756857 DOI: 10.1074/jbc.273.41.26295] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
beta-Aspartyl di- and tripeptides are common constituents of mammalian metabolism, but their formation and catabolism are not fully understood. In this study we provide evidence that glycosylasparaginase (aspartylglucosaminidase), an N-terminal nucleophile hydrolase involved in the hydrolysis of the N-glycosidic bond in glycoproteins, catalyzes the hydrolysis of beta-aspartyl peptides to form L-aspartic acid and amino acids or peptides. The enzyme also effectively catalyzes the synthesis of beta-aspartyl peptides by transferring the beta-aspartyl moiety from other beta-aspartyl peptides or beta-aspartylglycosylamine to a variety of amino acids and peptides. Furthermore, the enzyme can use L-asparagine as the beta-aspartyl donor in the formation of beta-aspartyl peptides. The data show that synthesis and degradation of beta-aspartyl peptides are new, significant functions of glycosylasparaginase and suggest that the enzyme could have an important role in the metabolism of beta-aspartyl peptides.
Collapse
Affiliation(s)
- T Noronkoski
- Department of Clinical Chemistry, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
| | | | | | | | | |
Collapse
|