Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The reactivities of phenylglyoxal (PGO), glyoxal (GO), and/or methylglyoxal (MGO) with several proteins, including ribonuclease A [EC 3.1.4.22] and its derivatives, alpha-chymotrypsin [EC 3.4.21.1], trypsin [EC 3.4.21.4], lysozyme [EC 3.2.1.17], pepsin [EC 3.4.23.1], rennin [EC 3.4.23.4], thermolysin, and insulin and its B chain, have been examined. From analyses of the reaction products, PGO was shown to be the most specific for arginine residues. GO and MGO also reacted rapidly with arginine residues, but they also reacted with lysine residues to a significant extent. A side reaction with N-terminal alpha-amino groups was observed with each of these reagents. 2. Two arginine residues out of four in ribonuclease A, two out of three in alpha-chymotrypsin, one out of two in trypsin, one out of two in pepsin, and one out of five in rennin appeared to react with PGO fairly rapidly, indicating a difference in the relative accessibility of these residues by the reagent. Extensive modification of the arginine residues by PGO occurred with RCM-derivatives of ribonuclease A and insulin B chain. The N-terminal isoleucine residues of alpha-chymotrypsin and trypsin appeared to be unreactive with PGO because of salt bridge formation with an aspartyl residue. The activity of alpha-chymotrypsin toward N-benzoyl-L-tyrosine ethyl ester and the lytic activity of lysozyme were lost rapidly on treatment with PGO, as in the case of ribonuclease A. Pepsin and rennin were only partially inactivated by reaction with PGO.
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PMID:Further studies on the reactions of phenylglyoxal and related reagents with proteins. 32 41

Five pepsinogens were purified from gastric mucosa of Japanese monkey by DEAE-cellulose column chromatography and Sephadex G-100 gel filtration. Each was shown to be homogeneous by polyacrylamide disc gel electrophoresis. They were designated as pepsinogens I, II, III-1, III-2, and III-3, respectively, based on the elution profile on DEAE-cellulose chromatography. The molecular weights of pepsinogens I and II were 48,000 and 43,000, respectively, and those of the other three were 40,000. Each pepsinogen was converted to pepsin [EC 3.4.23.1] by acidification, and some characteristics, e.g. the pH dependence of activity, sensitivity to various inhibitors, stability to alkali, and hydrolytic activity toward N-acetyl-L-phenylalanyl-3,5-diiodo-L-tyrosine (APDT), were determined. The characteristics of pepsins I and II were the same, and those of pepsins III-1, III-2, and III-3 were similar. Pepsin III-3 showed high stability to alkali (pH 8.0), while the others were less stable. Each pepsin hydrolyzed APDT and was inhibited by acid protease-specific inhibitors, e.g. pepstain, diazoacetyl-DL-norleucine methyl ester (DAN), 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP), and p-bromophenacyl bromide. The compositions of pepsins I and II were the same, indicating that they are the same protein, and those of pepsins III-1, III-2, and III-3 resembled that of human pepsin. The diversity of pepsinogens and pepsins is discussed in comparison with pepsinogens and pepsins from other animals.
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PMID:Pepsinogens and pepsins from gastric mucosa of Japanese Monkey. Purification and characterization. 82 Jun 94

1. Three pepsins were purified from the gastric mucosa of Atlantic cod (Gadus morhua). 2. The enzymes, called Pepsin I and Pepsin IIa and b, had isoelectric points 6.9, 4.0 and 4.1, respectively, and digested hemoglobin at a maximal rate at a pH of approximately 3. 3. They resembled bovine cathepsin D in being unable to digest the mammalian pepsin substrate N-acetyl-L-phenylalanyl-3,5-diiodo-L-tyrosine. 4. Specificity constants (kcat/Km) for the cod pepsins were lower than for porcine pepsin, and they expressed higher substrate affinity and physiological efficiency at pH 3.5 than at pH 2. 5. The cod pepsins are glycoproteins, and their amino acid composition resembles that of porcine cathepsin D more than that of porcine pepsin. 6. The N-terminal sequence of Atlantic cod pepsins is substantially different from that of porcine pepsin. This indicates a significant evolutionary gap between fish and mammalian pepsins.
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PMID:Catalytic properties and chemical composition of pepsins from Atlantic cod (Gadus morhua). 211 46

Affinity chromatography of porcine protease and its zymogen was carried out on immobilized components of specific substrate used for the pepsin determination. For the immobilization of N-acetyl-L-phenylalanine and iodinated derivative of L-tyrosine, divinyl sulfone activated Sepharose was used. Ligands with blocked amino group and free carboxyl one were linked to Sepharose via ethylene diamine spacer using carbodiimide reaction. Conditions of affinity chromatography of porcine pepsin and pepsinogen on the prepared carriers were optimized: the effect of pH, ionic strength and a nature of the buffers used on adsorption of the enzyme and zymogen to an affinity carrier, as well as their elution was studied. The following parameters were taken into consideration: capacity of the prepared affinity matrices, reproducibility of experiments and the enzyme stability. Pepsin was adsorbed to both immobilized ligands at pH 3.5-4.0; for the elution of the enzyme it was necessary to increase ionic strength (up to 0.5 M). For the adsorption of pepsinogen pH 5.2 was found to be optimum, for its desorption, an increase of ionic strength was used.
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PMID:Affinity chromatography of porcine pepsin and pepsinogen using immobilized ligands derived from the specific substrate for this enzyme. 1469 43