Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three intracellular proteinases termed A, B and C were purified to homogeneity from the unicellular form of the yeast Candida albicans. Enzyme A is an aspartic proteinase that acts on a variety of proteins. Its optimal pH is around 5 and it is displaced to 6.5 by KSCN. It is not significantly inhibited by PMSF, TLCK (Tos-Lys-CHCl2) or soybean trypsin inhibitor but it is inhibited by pepstatin. Its molecular weight is 60 000. Enzyme B is a dipeptidase that acts on esters or on dipeptides without blocks in either the carboxyl or amino ends. Its pH optimum is around 7.5 and the molecular weight is 57 000. It is inhibited by PMSF, TLCK and DANME (N2Ac-Nle-OMe). Proteinase C is an aminopeptidase with an optimum pH around 8. Its molecular weight was 67 000 when determined by SDS gel electrophoresis and 243 000 when determined by gel weight was 67 000 when determined by SDS gel electrophoresis and 243 000 when determined by gel filtration. It is active towards dipeptides in which at least one amino acid is apolar and is not active when the N-terminal amino acid is blocked. It is inhibited by EDTA or o-phenanthroline and activated by several divalent cations.
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PMID:Purification and properties of three intracellular proteinases from Candida albicans. 351 44

Aminopeptidase III activity was demonstrated in extracts from several different mammalian lenses by the hydrolysis of Arg-MCA at pH 6.0. No more than a two-fold difference was seen in overall specific activity. Sections of bovine lenses were removed from the periphery to the center and assayed. A sharp decline in activity was observed in the inner cortical region, and little or no activity was observed in the lens nucleus. This correlated with an increase in the presence of low molecular weight peptides as determined by SDS polyacrylamide gel electrophoresis. The properties of the aminopeptidase from human lens tissue were the same as those previously reported for the purified enzyme from bovine lens. The aminopeptidase activity of normal and cataractous lenses was compared using 4 different substrates. The cataractous lenses had significantly less total aminopeptidase activity. However, little difference in specific activity was observed based on soluble lens protein content. Similarly, electrophoretic separations of normal and cataractous soluble proteins showed little or no differences in the content of low molecular weight peptides. Therefore, this major human lens aminopeptidase remains functional in the cataractous state.
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PMID:Aminopeptidase III activity in normal and cataractous lenses. 372 Mar 44

A nucleoside antibiotic, ascamycin (9-beta-[5'-0-(N-L-alanyl) sulphamoyl-D-ribofuranosyl]-2-chloroadenine), has a selective antibacterial activity against Xanthomonas species. When ascamycin was dealanylated, dealanylascamycin showed a broad antibacterial activity against various Gram-negative and Gram-positive bacteria. Xanthomonas citri is susceptible to ascamycin by virtue of the ascamycin-dealanylating enzyme on the cell surface [Osada & Isono (1985) Antimicrob. Agents Chemother. 27, 230-233]. The enzyme (Xc aminopeptidase) was purified from X. citri cells by successive DEAE-cellulose, chromatofocusing and Sephadex G-100 column chromatography to a homogeneous state. The purified enzyme exhibited a single band with an Mr of 38 000 in SDS/polyacrylamide-gel electrophoresis. Gel filtration on a calibrated column indicated a similar Mr value. The isoelectric point of the enzyme was 5.7. The enzyme catalysed the hydrolysis of the alanyl group of ascamycin and liberated alanine from the sulphamoyl nucleoside. The enzyme also catalysed the hydrolysis of L-proline beta-naphthylamide and L-alanine beta-naphthylamide. The optimal pH and temperature for enzyme activity were pH 7.5-8.0 and 35-40 degrees C respectively. The enzyme was inhibited by thiol-enzyme inhibitors (i.e. rho-chloromercuribenzoate and N-ethylmaleimide), but was not affected by various naturally occurring aminopeptidase inhibitors (i.e. amastatin, bestatin, pepstatin and leupeptin). Mn2+ and Mg2+ activated the enzyme, whereas Cu2+, Zn2+ and Cd2+ were inhibitory.
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PMID:Purification and characterization of ascamycin-hydrolysing aminopeptidase from Xanthomonas citri. 375 35

We have studied some aspects of the morphological and biochemical differentiation of the foetal guinea-pig colonic epithelium. At day 40 the epithelium was organised in ridges and appeared pseudo-stratified. Folding of the epithelium, followed by villus formation, occurred between days 45 and 55, and by day 50 mucus-secreting goblet cells appeared at the bases of the colonic villi. By day 55 most epithelial cells, including goblet cells, possessed numerous microvilli which, by day 65, had become organised into well developed brush-borders. Between day 55 and term (day 65-68) mucosal depth increased markedly and the colon attained its final glandular morphology. Biochemical studies showed the specific activities of the microvillar hydrolases to be much lower in the washed colon than in either foetal meconium or small intestine at all times during development. Furthermore, a membrane fraction highly enriched in microvillus hydrolase activities was prepared from foetal colonic meconium using techniques originally devised to isolate the foetal small intestinal microvillus membrane. This meconial subfraction was almost identical in polypeptide composition to the highly-purified foetal small intestinal microvillus membrane. Identification of the colonic microvillus membrane was hampered by the absence of reliable membrane markers. Nevertheless, a fraction 14-fold enriched in aminopeptidase activity was prepared from day 40 foetal colon and its polypeptide composition compared by SDS-PAGE to that of the small intestinal microvillus membrane at the same age.
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PMID:Structural and biochemical differentiation of the guinea-pig colon during foetal development. 404 35

An intracellular N-terminal exopeptidase isolated from cell extracts of Streptococcus durans has been purified 470-fold to homogeneity (specific activity of 12.0 mumol/min per mg). In the absence of thiol compounds, the purified aminopeptidase undergoes a slow oxidation with a 70% loss of activity, which can be restored by the addition of 2 mM beta-mercaptoethanol. The purified aminopeptidase (Mr 300000) preferred L-peptide and arylamide substrates with small nonpolar or basic side chains. SDS electrophoresis yielded a single protein band corresponding to a molecular weight of 49400, suggesting that the native enzyme is a hexameric protein. The enzyme-catalyzed hydrolysis of L-alanyl-p-nitroanilide exhibited a bell-shaped pH dependence for log Vmax/Km (pK1 = 6.35; pK2 = 8.50) while the log Vmax versus pH profile showed only an acid limb (pK = 6.35). Methylene blue-sensitized photooxidation of the enzyme resulted in the complete loss of activity, while L-leucine, a competitive inhibitor, partially protected against this inactivation. Amino acid analysis indicated that this photooxidative loss of activity corresponded to the modification of one histidine residue per enzyme monomer. N-Ethylmaleimide (100 mM) caused a 78% reduction in enzyme activity. Treatment of the enzyme with 1.0 mM hydrogen peroxide resulted in the oxidation of two cysteine residues per enzyme monomer and caused a 70% decrease in the catalytic activity.
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PMID:Purification and characterization of an intracellular N-terminal exopeptidase from Streptococcus durans. 643 Mar 50

In order to gain more insight into the adaptative mechanism of intestinal enzymes to dietary factors in rats, modifications in the activities of disaccharidases and aminopeptidase were measured after refeeding of a 70% solution of sucrose for 15 h following a 2-day fast. Mature epithelial cells from the villus and immature cells from the crypt were isolated after sequential removal of the cells along the villus-crypt axis. Synthesis of brush border disaccharidases was determined by measuring [3H]valine incorporation into proteins. 1. In the whole mucosa, a highly significant increase in sucrase and maltase activities and a significant drop in aminopeptidase activity was observed in the brush border membranes after sucrose refeeding. 2. Stimulation of sucrase and maltase activities in sucrose refed rats was produced mainly in the immature cells of the crypt and lower villus compartment. 3. After separation of the brush border proteins by SDS gel electrophoresis from villus and crypt cells of sucrose refed rats, major incorporation of the radioactive precursor occured in the protein bands corresponding to sucrase and maltase activities of the lower villus and crypt cell brush borders. These findings demonstrate that sucrase stimulation by sucrose occurs mainly in the immature epithelial cells and that the substrate induces de novo synthesis of sucrase molecules.
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PMID:Effect of sucrose refeeding on disaccharidase and aminopeptidase activities of intestinal villus and crypt cells in adult rats. Evidence for a sucrose-dependent induction of sucrase in the crypt cells. 677 Sep 8

Pure dipeptidyl peptidase IV (X-prolyl dipeptidyl aminopeptidase), which did not contain aminopeptidase activity at all, was rapidly prepared from the human submaxillary gland by chromatography with concanavalin A-Sepharose and Gly-Pro-NH-(CH2)6-NH-Sepharose. The entire purification took only 3 days. Aminopeptidase, which was very difficult to separate from dipeptidyl peptidase IV by various chromatographic procedures, could be completely removed by chromatography with Gly-Pro-NH-(CH2)6-NH-Sepharose. On SDS gel electrophoresis the purified enzyme gave a single band with a molecular weight of 116,000. The apparent molecular weight of the enzyme was estimated to be 225,000 by gel filtration. Therefore, the enzyme consists of two identical subunits. It did not hydrolyze Ala p-nitroanilide at all, but the hydrolysis of the p-nitroanilides of Gyl-Pro, Lys-Pro and Arg-Pro at pH 8.0 was nearly specific.
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PMID:Rapid chromatographic purification of dipeptidyl peptidase IV in human submaxillary gland. 699 15

For this investigation highly purified brush border membranes from human small intestine, prepared according to the method described in the preceding paper [1], have been used. Solubilisation of brush border membrane proteins by sodium dodecyl sulphate, Triton X-100 and papain followed by electrophoresis in polyacrylamide gels revealed six distinct peptide hydrolases. These included the enzymes aminopeptidase A (EC 3.4.11.7), dipeptidylpeptidase IV (EC 3.4.14.-), gamma-glutamultranspeptidase (EC 2.3.2.2) and aminopeptidase M (EC 3.4.11.2), which were clearly separable on polyacrylamide gels after solubilisation with Triton X-100 or papain. Activity recovered in the aminopeptidase M peak in the above gel system could be resolved into two distinct peptidases in addition to aminopeptidase M, by SDS-gel-electrophoresis. One of these peptidases was most active towards aliphatic tripeptide (aminopeptidase 1) while the other appeared to be specific for dipeptides (aminopeptidase 2).
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PMID:Peptide hydrolases of the human small intestinal mucosa: identification of six distinct enzymes in the brush border membrane. 699 49

A novel aminopeptidase was purified by high performance liquid chromatography from a cytosoluble 100,000 g extract of Candida albicans on the basis of its ability to cleave L-arginine 7-amino-4-methylcoumarin. The purification factor was 36 and the yield was 20%. The native enzyme had a mol. wt of 52 kDa as demonstrated by SDS-PAGE in the presence or absence of reducing conditions and exhibited an iso-electric point of 4.3. The aminopeptidase showed optimum activity at pH 7.2, a Michaelis constant of c. 50 microM and a Vmax at 19 mM AMC released/min/mg of protein for L-Arg-AMC. This enzyme was shown to cleave at low affinity L-leucine-7-amino-4-methylcoumarin as demonstrated by the spectrofluorimetric method. The enzyme was strongly inhibited by specific metallo-enzyme inhibitors-EDTA and o-phenanthroline. Furthermore, there is evidence that a similar or identical enzyme occurs in other C. albicans clinical isolates and other Candida spp.
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PMID:Purification and characterisation of a metallopeptidase of Candida albicans. 756 90

The principal digestive proteinases of the gypsy moth, Lymantria dispar, larval midgut were identified, and the subcellular distribution of the enzyme activities was determined. Proteinase activities of fifth-instar larvae were largely attributed to two luminal serine proteinases, a trypsin-like enzyme (TLE) and an elastase 2-like enzyme (ELA). TLE was purified to homegeneity by benzamidine-Sepharose affinity chromatography. With respect to size (M(r) = 25 kDa), substrate specificity, and interaction with trypsin inhibitors, the gypsy moth enzyme resembled mammalian pancreatic trypsin and trypsin-like enzymes from other insects. Gypsy moth elastase (ELA) was purified from the benzamidine-Sepharose flow-through by mono-Q FPLC. ELA exhibited a slightly smaller size (M(r) = 24 kDa) than TLE. The insect enzyme was inhibited by DFP and chymostatin but was unaffected by TPCK. ELA exhibited little esterolytic activity with BTEE. Succinyl-Ala-Ala-Pro-Leu p-nitroanilide was one of the best substrates for ELA, which is characteristic of elastase 2. TLE and ELA constituted c. 6% of the total soluble protein in midgut lumen of actively feeding fifth-instar larvae. Chymotrypsin and carboxypeptidase activities were not detected in any midgut fraction examined. The brush border membrane (BBM) leucine aminopeptidase (LAP) was isolated from CHAPS-solubilized BBM by FPLC. SDS-PAGE results indicated that the aminopeptidase has an apparent molecular size of c. 100 kDa. The aminopeptidase was inhibited by bestatin and was unaffected by serine proteinase inhibitors.
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PMID:Gypsy moth midgut proteinases: purification and characterization of luminal trypsin, elastase and the brush border membrane leucine aminopeptidase. 771 46


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