Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method was elaborated for obtaining polyacrylamide gel zymograms of the cobalt-activated acylase after electrophoresis. Two fractions of the acylase showing activity towards N-chloroacetyl-gamma-L-glutamyl-beta-naphthylamide were found in human kidney, liver and intestine. The two fractions isolated from liver differ in substrate specificity, heat resistance, response to metal ions, inhibition by deaminated dipeptides, and in molecular weight. They differ also from other N-acylamino acid amidohydrolases: aminoacylase (EC 3.5.1.14) and aspartoacylase (EC 3.5.1.15).
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PMID:Polymorphism of the cobalt-activated acylase in human tissues. 2 51

Canavan disease (CD), a rare recessive autosomal genetic disorder, is characterized by early onset and a progressive spongy degeneration of the brain involving loss of the axon's myelin sheath. After a relatively normal birth, homozygous individuals generally develop clinical symptoms within months, and usually die within several years of the onset of the disease. A biochemical defect associated with this disease results in reduced activity of the enzyme N-acetyl-L-aspartate amidohydrolase (aspartoacylase) and affected individuals have less ability to hydrolyze N-acetyl-L-asparate (NAA) in brain and other tissues. As a result of aspartoacylase deficiency, NAA builds up in extracellular fluids (ECF) and is excreted in urine. From an analysis of the NAA biochemical cycle in various tissues of many vertebrate species, evidence is presented that there may be two distinct NAA circulation patterns related to aspartoacylase activity. These include near-field circulations in the brain and the eye, and a far-field systemic circulation involving the liver and kidney, the purpose of which in each case is apparently to regenerate aspartate (Asp) in order for it to be recycled into NAA as part of the still unknown function of the NAA cycle. Based on the authors' analysis, they have also identified several metabolic outcomes of the genetic biochemical aspartoacylase lesion. First, there is a daily induced Asp deficit in the central nervous system (CNS) that is at least six times the static level of available free Asp. Second, there is up to a 50-fold drop in the intercompartmental NAA gradient, and third, the ability of the brain to perform its normal intercompartmental cycling of NAA to Asp is terminated, and as a result, the only remaining long-term source of Asp for NAA synthesis is via nutritional supplementation of Asp or its metabolic precursors. Finally, the authors identify a potential maternal-fetal interaction that may be responsible for observed normal fetal development in utero, and that provides a rationale for, and suggests how, CD might respond to far-field nutritional, transplantation, or genetic engineering techniques to alter the course of the disease.
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PMID:Canavan disease. Analysis of the nature of the metabolic lesions responsible for development of the observed clinical symptoms. 940 92

Mercapturates (S-substituted N-acetyl-L-cysteines) are terminal metabolites formed by the glutathione-dependent metabolism of electrophilic xenobiotics, including haloalkenes. Acylases catalyze the hydrolysis of N-acyl-L-amino acids, including many xenobiotic-derived mercapturates, to give fatty acids and amino acids as products. Although several acylases have been identified, the acylases that catalyze the deacetylation of the haloalkene-derived mercapturates have not been identified and characterized. Acylase I catalyzes the deacetylation of some haloalkene-derived mercapturates, including S-(1,1,2, 2-tetrafluoroethyl)-N-acetyl-L-cysteine, S-(2-chloro-1,1, 2-trifluoroethyl)-N-acetyl-L-cysteine, and S-(2-bromo-1,1, 2-trifluoroethyl)-N-acetyl-L-cysteine [Uttamsingh, V., et al. (1998) Chem. Res. Toxicol. 11, 800-809]. In the studies presented here, we identified a rat kidney acylase that catalyzed the hydrolysis of the haloalkene-derived mercapturates S-(1, 2-dichlorovinyl)-N-acetyl-L-cysteine, S-(1,2,3,4,4-pentachloro-1, 3-butadienyl)-N-acetyl-L-cysteine, and S-(2,2-dibromo-1, 1-difluoroethyl)-N-acetyl-L-cysteine. The substrate selectivity and amino acid sequence of the purified rat kidney acylase were studied. Although the sequence of the purified rat kidney acylase was somewhat identical with that of aspartoacylase, it did not catalyze the hydrolysis of N-acetyl-L-aspartate.
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PMID:Acylase-catalyzed deacetylation of haloalkene-derived mercapturates. 1052 69

Despite its growing use as a radiological indicator of neuronal viability, the biological function of N-acetylaspartate (NAA) has remained elusive. This is due in part to its unusual metabolic compartmentalization wherein the synthetic enzyme occurs in neuronal mitochondria whereas the principal metabolizing enzyme, N-acetyl-L-aspartate amidohydrolase (aspartoacylase), is located primarily in white matter elements. This study demonstrates that within white matter, aspartoacylase is an integral component of the myelin sheath where it is ideally situated to produce acetyl groups for synthesis of myelin lipids. That it functions in this manner is suggested by the fact that myelin lipids of the rat optic system are well labeled following intraocular injection of [14C-acetyl]NAA. This is attributed to uptake of radiolabeled NAA by retinal ganglion cells followed by axonal transport and transaxonal transfer of NAA into myelin, a membrane previously shown to contain many lipid synthesizing enzymes. This study identifies a group of myelin lipids that are so labeled by neuronal [14C]NAA, and demonstrates a different labeling pattern from that produced by neuronal [14C]acetate. High performance liquid chromatographic analysis of the deproteinated soluble materials from the optic system following intraocular injection of [14C]NAA revealed only the latter substance and no radiolabeled acetate, suggesting little or no hydrolysis of NAA within mature neurons of the optic system. These results suggest a rationale for the unusual compartmentalization of NAA metabolism and point to NAA as a neuronal constituent that is essential for the formation and/or maintenance of myelin. The relevance of these findings to Canavan disease is discussed.
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PMID:Intraneuronal N-acetylaspartate supplies acetyl groups for myelin lipid synthesis: evidence for myelin-associated aspartoacylase. 1152 Aug 94