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)

Membrane suspensions prepared from Micrococcus luteus (sodonensis) in both the exponential and stationary phases of growth contained a transglycosidase activity capable of synthesizing linear peptidoglycan. Exponential-phase membranes also contained an N-acetylmuramyl-L-alanine amidase activity which degraded the peptidoglycan as it was formed. The product of this amidase was purified and found to be free pentapeptide. The amidase was specific for peptidoglycan and could not attack lower-molecular-weight substrates even though the susceptible bond was present. Crude cell wall preparations isolated from exponential-phase cells also contained high levels of amidase. This cell wall-bound amidase would preferentially degrade in vitro-synthesized peptidoglycan over its own cell wall. Amidase activity could be solubilized from both cell walls and membranes by Triton X-100 treatment, butanol extraction, or LiCl extraction. Both membrane- and cell wall-derived amidases, solubilized by LiCl extraction, appeared to be of high molecular weight (greater than 150,000). Once solubilized, these wall- and membrane-derived amidases could attack the cross-bridged peptidoglycan of purified native cell walls, whereas bound amidases could not.
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PMID:Amidase activity involved in peptidoglycan biosynthesis in membranes of Micrococcus luteus (sodonensis). 93 48

Variant surface glycoproteins (VSGs) of Trypanosoma brucei contain two distinct glycosylation sites: (1) N-linked glycans within the protein portion of the molecules, and (2) the glycosyl-phosphatidylinositol (GPI) membrane anchor. Since galactose residues show uncommon alpha-glycosidic linkages in the GPI membrane anchor, we were prompted to investigate galactosylation of the GPI anchor. On comparing a trypanosome clone galactosylated exclusively in N-glycans (clone MITat 1.5) with clones galactosylated predominantly in the glypiated membrane anchor (clones MITat 1.4, MITat 1.6 and AnTat 1.8), clone MITat 1.5 showed a 10-fold increased enzyme activity when using a protocol including Triton X-100 to assay UDPgalactose:N-acetylglucosaminyl glycopeptide beta 1,4-galactosyltransferase (EC 2.4.1.38). Only the VSG of clone MITat 1.5 could be radiochemically labelled with UDP[14C]galactose, and galactosylation of N-glycans was confirmed by digestion with peptide-N4-(N-acetylglucosaminyl)asparagine amidase (PNGase F). However, in a modified enzyme assay without detergent, galactosyltransferase activity was increased considerably (15-fold) in clone MITat 1.4. VSG galactosylation of clones MITat 1.4, MITat 1.6 and AnTat 1.8 was readily detected by fluorography of the respective SDS/polyacrylamide gels, suggesting that galactosyltransferase activity modifies the VSG membrane anchor in these clones. In this case, [14C]galactose labelling of immunoprecipitated VSG (clone MITat 1.4) was resistant to the release of N-glycans by PNGase F treatment, and thus revealed galactosylation in vitro of a VSG membrane anchor. Exoglycosidase digestions of VSG MITat 1.4 confirmed the presence of alpha-linked galactose residues. We suggest that these specific alpha-galactosyltransferases are inhibited by the action of detergent, but can be activated in a detergent-free buffer system.
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PMID:Identification of two distinct galactosyltransferase activities acting on the variant surface glycoprotein of Trypanosoma brucei. 153 12

Acrosin, a sperm-specific acrosomal proteinase, has an essential role in the fertilization process. Low levels of acrosin appear to be associated with subfertility and infertility, and the acrosin activity of spermatozoa may potentially be a useful indicator of semen quality. The standard acrosin tests employed by research laboratories are too complicated and/or time consuming for clinical use; therefore, a simple assay has been developed to assess total acrosin activity (acrosin and activatable proacrosin). To perform the test, liquefied semen is centrifuged over Ficoll, the washed sperm pellet is suspended in a detergent (Triton X-100)-substrate (N-alpha-benzoyl-DL-arginine p-nitroanilide) buffer, pH. 8.0, and the amidase activity is determined spectrophotometrically after a 3-hour incubation period. Amidase activity can be inhibited with benzamidine, indicating that the activity is primarily or entirely due to acrosin. The absence of detergent in the incubation medium results in greatly reduced activity. The assay is repeatable, linear with increasing sperm concentration, sensitive to a lower limit of 2 x 10(6) spermatozoa, and the results correspond to those obtained with a standard acrosin extraction and assay technique. Storage of ejaculates at 3 to 6 C or at 22 to 24 C for 24 hours does not affect the acrosin activity significantly but much higher temperatures can cause a loss of activity. Freezing ejaculates results in a large decrease in sperm acrosin activity. Leukocytes show minimal activity in the assay. Sperm populations prepared by a swim-up procedure average approximately a 2-fold higher acrosin activity than the original ejaculates. Preliminary experiments indicate that the average sperm acrosin activity of ejaculates whose spermatozoa successfully fertilize human eggs in vitro is significantly higher than those that do not fertilize eggs.
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PMID:A simple, clinical assay to evaluate the acrosin activity of human spermatozoa. 274 33

Enzymatic deacylation of the lipopolysaccharide isolated from a Salmonella Rd mutant by a cell-free preparation from Acanthamoeba castellanii has been studied. The degradation was found to be dependent on the presence of a surface-active component (Triton X-100) in the reaction mixture. The lipid A part of the lipopolysaccharide was the primary target of the enzymes, which cleaved with high efficiency the ester-bound long-chain nonhydroxylated and 3-hydroxylated acyl residues, i.e. lauric, myristic, palmitic and 3-hydroxymyristic acid. The cell-free preparation also exhibited amidase activity cleaving about 50% of the amide-bound 3-hydroxymyristic acid residues. In addition the extract proved to possess phosphatase activity liberating ester-bound and glycosidically bound phosphate groups of lipid A. On the other hand, the glucosaminyl-beta 1,6-glucosamine disaccharide was not degraded and remained bound to the oligosaccharide part (heptose/3-deoxyoctulosonic acid) of the lipopolysaccharide.
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PMID:In vitro deacylation of lipopolysaccharide of Salmonella minnesota by Acanthamoeba castellanii enzymes. 300 30

Rat liver microsomes and mitochondria contain an amidohydrolase which catalyzes the hydrolysis of N-acylethanolamine to ethanolamine and fatty acid. The enzyme is active over a wide range of pH, does not require divalent cations, and is inhibited by sulfhydryl-reactive agents. The detergents Triton X-100, sodium cholate, and sodium dodecyl sulfate are also inhibitory, but sodium taurodeoxycholate has little effect and was therefore used to solubilize the enzyme. The solubilized enzyme exhibits high substrate specificity for long-chain amides of ethanolamine. Amides of propanolamine or higher homologs are hydrolyzed at a drastically slower rate, and isomers prepared from long-chain amine and short-chain hydroxy acid are neither substrates nor inhibitors of the enzyme. Neither ceramide (N-acylsphingosine) nor N,O-diacylethanolamine is hydrolyzed. Both particulate and soluble enzyme preparations also catalyze the synthesis of N-acylethanolamine from ethanolamine and fatty acid, probably by the amidohydrolase acting in reverse.
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PMID:Properties of rat liver N-acylethanolamine amidohydrolase. 405 75

A radioisotopic assay for adenosine deaminase (EC 3.5.4.4) is described together with its application in investigating the activity of the enzyme in rat cerebral cortex. Activity of the adenosine deaminase was determined to be 115nmol/min per g of tissue, measured in isoosmotic sucrose dispersions of the neocortex, and to be 170nmol/min per g of tissue after treatment with Triton X-100. The enzyme was concluded to be largely cytoplasmic, with a K(m) of 54-57mum for adenosine. Action of the deaminase, and other aspects of the metabolism of adenosine in intact neocortical tissue, were quantitatively appraised on the basis of the newly determined characteristics.
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PMID:Rat cerebral-cortex adenosine deaminase activity and its subcellular distribution. 446 74

N4-Long-chain fatty acyl-1-beta-D-arabinofuranosylcytosine amidohydrolase, a metabolizing enzyme for N4-acyl derivatives of 1-beta-D-arabinofuranosylcytosine with long-chain fatty acids, was purified from mouse liver microsomes. The purification was accomplished by solubilization of liver microsomes with Triton X-100, diethylaminoethyl cellulose chromatography, gel filtrations, hydroxyapatite chromatography, and concanavalin A:Sepharose chromatography. On sodium dodecyl sulfate:polyacrylamide gel electrophoresis, the purified enzyme preparation produced a single protein band with a molecular weight of 54,000. The enzyme had an optimal pH of 9.0, and the Michaelis constant for N4-palmitoyl-1-beta-D-arabinofuranosylcytosine was 67 microM. The thiols such as dithiothreitol or 2-mercaptoethanol stabilized the enzyme and stimulated its activity. p-Chloromercuribenzoate, N-ethylmaleimide, diisopropylfluorophosphate, and phenylmethylsulfonyl fluoride strongly inhibited the reaction. Bovine serum albumin markedly stimulated the enzyme activity, whereas detergents such as Triton X-100, deoxycholate, and sodium dodecyl sulfate had little effect. The enzyme did not require monovalent or divalent cations. Among the series of N4-acyl derivatives of 1-beta-D-arabinofuranosylcytosine with different chain lengths of acyl residues, the purified enzyme preferentially hydrolyzed the derivatives with long-chain fatty acids (C12 to C18), and N4-palmitoyl-1-beta-D-arabinofuranosylcytosine was the most susceptible. The purified enzyme was inactive on various N-acylamino acids, amides, oligopeptides, proteins, N-acylsphingosines (ceramides), triglyceride, lecithin, and lysolecithin. These results suggest that N4-long-chain fatty acyl-1-beta-D-arabinofuranosylcytosine amidohydrolase may be a new type of linear amidase.
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PMID:Purification and characterization of an amidohydrolase for N4-long-chain fatty acyl derivatives of 1-beta-D-arabinofuranosylcytosine from mouse liver microsomes. 669 3

The pineal aryl acylamidase (AAA) activity has been demonstrated and characterized for the first time using ONAc as a substrate. The pineal AAA activity in the presence of 0.05% Triton X-100 was linear with protein concentration up to 1 mg and with incubation time up to 1 hour. Both the rat and bovine pineal showed a pH optimum at 5.0. The in vitro and in vivo effects of several classes of drugs on the pineal AAA activity were examined. At 0.1 mM, 5-HT, N-acetyl-5HT, melatonin, d-LSD, l-LSD, methiothepin, DA, chlorimipramine, imipramine, pargyline, TH C and harmaline significantly inhibited the rat pineal AAA activity by 19-51%. N-Acetyl-5-HT was the most potent in vitro inhibitor. However, at the same concentration, NE, 6-MeO-harman and eserine did not show any effect on the enzyme activity. Lineweaver-Burk plot indicated a competitive type of in vitro inhibition of the pineal AAA activity by melatonin. Acute subcutaneous injection of low doses (25-50 mg/kg) THBC harmaline, desipramine and protriptyline markedly inhibited the rat pineal AAA activity but at higher doses (75-100 mg/kg) the inhibition was reduced. On the contrary, RO4-4602 (200-800 mg/kg) greatly enhanced (1.5-2.3 fold) the enzyme activity, inversely proportional to the doses given. In view of the differential effects of these drugs on the brain and pineal AAA, it seems unlikely that they would be the same enzyme.
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PMID:Pineal aryl acylamidase: effects of melatonin, serotonin-related compounds, beta-carbolines, RO4-4602 and antidepressants. 670 61

1. The serotonin (5-HT) sensitive brain aryl acylamidase (AAA) has received considerable attention due to its potential involvement in 5-HT action mechanism in CNS. 2. Multiple forms, AAA-1 and 2, have been separated by ammonium sulfate precipitation of brain extract and subsequent gel filtration. 3. Their chemical properties have been characterized and differentiated by effects of several classes of drugs including d-LSD, 5-HT, 5-HT related compounds and tetrahydro-beta-carbolines on their enzyme activities. 4. In the rat brain, AAA-1 shows highest specific activity in corpus striatum and lowest activity in cerebellum whereas AAA-2 shows highest specific activity in cerebellum and lowest activity in corpus striatum. 5. Subcellularly, AAA-1 exhibits highest specific activity in synaptosomal fraction of rat corpus striatum, lowest activity in mitochondrial fraction and no activity in nuclear fraction while AAA-2 exhibits highest specific activity in microsomal fraction and lowest activity in nuclear fraction. 6. Triton X-100 treatment altered the subcellular distribution pattern of both AAA-1 and AAA-2. 7. AAA-2 is possibly associated with true acetylcholinesterase (AChE) in brain based on its inhibition by neostigmine but its identity with AChE needs further elucidation. 8. To determine the physiological role(s) for brain AAA, naturally occurring aromatic alkylamines other than melatonin need to be tested as possible substrate(s) for the enzyme activity.
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PMID:Brain aryl acylamidase. 675 8

Treatment of normal human brain mitochondria with a mixture containing Triton X-100 and urea resulted in solubilization of monoamine oxidase (MAO) exhibiting tyramine-, serotonine-, phenylethylamine- and dopamine deaminase activities at ratios similar to those characteristic for the initial mitochondria. A purified preparation of the enzyme was obtained after AH-Sepharose chromatography; it was shown that in the brain there were present four isoenzymes of MAO possessing different substrate specificity. Investigation of some properties of MAO (activity, solubilization and isozyme composition) from brain regions showed absence of asymmetry and higher enzymatic activity in the subcortical brain region as compared with right and left brain cortex.
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PMID:[Multiple forms of human brain monoamine oxidase]. 728 68


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