Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The sequence analysis of llama (Lama glama, Camelidae) hemoglobin is described. The chains were separated, cleaved by trypsin as previously described, quantitatively characterized and sequenced in the sequenator. The llama hemoglobin differs from the human hemoglobin in that it has 25 different amino acids in the alpha chain and 24 different amino acids in the beta chain. The interaction between protein and phosphate is discussed. The earlier finding that the O2 affinity of the llama hemoglobin is dependent on its content of 2, 3-bisphosphoglycerate is interpreted here as a mutation of the 2, 3-bisphosphoglycerate contact position beta2 His in human hemoglobin to beta2 Asn in llama hemoglobin, whereby one of the four 2, 3-bisphosphoglycerate contact points is interrupted. This interruption gives rise to a diminished reduction of intrinsic oxygen affinity in the hemoglobin molecule and explains, on a molecular basis, the increased oxygen affinity of the llama hemoglobin, and consequently, the high-altitude respiration of the llama. By analogy, the increased O2 affinity of human fetal hemoglobin is interpreted according to previous physiological investigations on blood and fetal hemoglobin by the inactivation of the phosphoglycerate contact point beta143 His in the adult hemoglobin by mutation to gamma 143 Ser in the fetal hemoglobin. With respect to respiration in horses (2, 3-bisphosphoglycerate contact beta2 Gln), measurement of atomic parameters show that the amido group of the glutamine is situated close enough to the 2, 3-bisphosphoglycerate oxygen to build a hydrogen bond with the phosphate. Consequently, the explanation of the low-altitude respiration of the horse lies in the fact that glutamine and histidine fulfill sterochemically an identical function.
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PMID:[The interaction between phosphate and protein, and the respiration of the llama, the human fetus and the horse (author's transl)]. 66 74

During studies on the amino acid sequence of bovine nasal cartilage collagen, the cyanogen bromide peptide alpha1(II)-CB11 was degraded to smaller peptides with trypsin. One of the tryptic peptides, T5, which contained 39 residues was shown by amino acid and sequence analyses to occur in a predominant form that contained glutamine at position 5 and in a second form with leucine at this site. In addition to the heterogeneity at this position, amino acid analyses of five different preparations revealed that the peptide with leucine contained a seryl residue not found in the major form. Sequence heterogeneity at a third position of alpha1(II) was demonstrated by the isolation of a hexapeptide (T2) from the trypsin digest of alpha1(II)-CB11 which contained 0.21 residue of alanine and 0.77 of leucine. Both the leucine and alanine of T2 were removed after the second cycle of subtractive Edman degradation. These data show that at least two types of alpha1(II) chains, designated as alpha1(II)Major and alpha1(II)Minor, exist in bovine nasal cartilage. Further considerations suggest that these two chains are probably not variants derived from allelic genes but are the products of separate genes.
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PMID:The covalent structure of cartilage collagen. Evidence for sequence heterogeneity of bovine alpha1(II) chains. 83 47

The purification and characterization of two related peptides making up the glutamine binding site of formylglycinamide ribonucleotide amidotransferase from chicken liver have been presented. An amino acid residue(s) involved in binding glutamine to the enzyme was selectively labeled with [14C]iodoacetate. The labeled enzyme was reduced, carboxymethylated, and degraded by trypsin to a large radioactive peptide that yielded on acid hydrolysis only cysteine as a radioactive carboxymethylated derivative. The tryptic peptide was further digested with a protease from Streptomyces griseus. Two radioactive fractions (I and II) were obtained by gel filtration on Sephadex G-25. Furthermore, two 14C-containing peptides have been isolated from fraction I by the aid of ion exchange chromatography on AG 1-X2, AG 50W-X2 and DEAE-cellulose. Upon acid hydrolysis both peptides yielded only carboxymethylcysteine (CMCys), cystine, glycine, valine, aspartic acid, and glutamic acid. The partial sequences of the amino residues in these peptides, which are located at the glutamine binding site, have been established by the dansyl-Edman method. The sequences of amino acids of peptides a and b are Gly-Val-Cys([14C]CM)-Asp-Asx-Cys(CM)-Glx...and Gly-Val-Cys([14C]CM)-Asx-Asx..., respectively. The two peptides are undoubtedly derived from the same segment of the original protein.
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PMID:Glutamine active site of formylglycinamide ribonucleotide amidotransferase. 2. Amino acid sequence of labeled peptides. 84 8

The membrane penicillinase of Bacillus licheniformis 749/C is a phospholipoprotein carrying extra residues of asparagine or aspartate, serine, glutamine or glutamate and glycine not present in the exoenzyme (Yamamoto, S., and Lampen, J.O. (1976) J. Biol. Chem. 251, 4095-4101). Cleavage of the membrane enzyme with trypsin yielded a phospholipipopeptide and a hydrophilic penicillinase differing from exopenicillinase only by the absence of the NH2-terminal lysine residue. Phosphatidylserine was isolated from a pronase digest of the phospholipopeptide. The partial sequence of the phospholipopeptide is: phosphatidylserine-(Ser3, Glx5, Asx7, Gly5)-Asp-Gin-Ser-Lys-COOH with the lysine being the NH2-terminal residue of the usual exoenzyme. The fatty acids present in the membrane enzyme and in the phospholipopeptide had essentially the same composition (predominantly n-16:0, ante iso-17:0, n-18:0, and n-18:1). These acids were also found in the total membrane lipids, although in very different proportions; thus, the phosphatidic acid residue of the phosphatidylserine is probably formed by the usual synthetic pathway for membrane phospholipids, but some special feature of the process affects the nature of the component fatty acids.
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PMID:The hydrophobic membrane penicillinase of Bacillus licheniformis 749/C. Characterization of the hydrophilic enzyme and phospholipopeptide produced by trypsin cleavage. 93 23

Agrocin 84, produced by Agrobacterium radiobacter K84, inhibited ribonucleic acid, deoxyribonucleic acid, and protein synthesis and amino acid transport in a susceptible, virulent strain of A. tumefaciens H-38-9. Cell motility was immediately stopped by action of the agrocin, 50% of the cells were killed within 15 min of contact, and the remainder were inhibited. Agrocin 84 is trypsin and pepsin resistant, but chemical analysis indicated a small peptide with a molecular weight of 2,500 containing six different amino acids, including nine molecules of glutamine or glutamic acid and seven molecules of serine.
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PMID:Chemical nature of agrocin 84 and its effect on a virulent strain of Agrobacterium tumefaciens. 98 92

Anti-ulcer effects of cetraxate, a new compound possessing anti-plasmin, anti-casein and anti-trypsin actions were investigated by using experimental gastric ulcer models in rats. Cetraxate, 300 mg/kg p.o. showed significant inhibitory effects of 65.3%, 70.0%, 30.2%, and 67.1% against aucte types of ulcers producing by aspirin, phenylbutazone, indomethacin, and pyloric ligature (Shay's ulcer), respectively. These effects were greater than those obtained by gefarnate and aluminum sucrose sulfate may be mainly attributed to the protecting action of this drug on gastric mucosa. Ctraxate further revealed remarkable inhibitory effects on chronic types of ulcers produced by acetic acid, clamping, and clamping-cortisone. In acetic acid ulcer in particular, cetraxate was found to have a dose-dependent inhibitory effect at doses over 50 mg/kg. Of test drugs including L-glutamine and methylmethionine sulfonium chloride, cetraxate showed the most remarkable inhibitory effect on beta-glucuronidase activity in ulcer tissue of these three types of ulcers. These findings suggest that cetraxate may prevent the connective tissue in the ulcer location from decomposition due to lysosomal enzymes such as beta-glucuronidase, thereby accelerating the recovery from ulcer.
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PMID:Anti-ulcer effects of 4'-(2-carboxyetyl) phenyl trans-4-aminomethyl cyclohexanecarboxylate hydrochloride (cetraxate) on various experimental gastric ulcers in rats. 100 3

A human alpha1-antitrypsin variant protein was purified to homogeneity from homozygous variant subjects (Pi-ZZ) who had a deficiency of plasma trypsin inhibitory capacity. Molecular weight, specific trypsin inhibitory capacity, and immunologic activity of the variant protein were identical to those of normal. Amino acids, N-acetylglucosamine, and hexose contents were closely similar in the normal and variant proteins, but the sialic acid content in the variant protein was significantly lower than normal. The structural difference between the normal and the variant alpha1-antitrypsin was elucidated by fingerprinting of their tryptic peptides. Two amino acid substitutions, i.e., glutamic acid in the normal protein to lysine in the variant protein, and glutamic acid in the normal protein to glutamine in the variant protein, were found.
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PMID:Molecular abnormality of human alpha1-antitrypsin variant (Pi-ZZ) associated with plasma activity deficiency. 108 27

1. 'Inhibitor fragment' isolated from human serum albumin degraded by rabbit cathepsin D is composed of one peptide chain with two intrachain disulphide bonds. There are two kinds of inhibitor molecules having different N-terminal amino acids: one is threonine and the other glutamine. 2. Fragment F1, isolated from inhibitor degraded by trypsin, is composed of two chains linked by a disulphide bond. There are three kinds of fragment F1. All have one alpha chain in common, which has an intrachain disulphide bond. They differ by the nature of the chain, which is linked to the alpha chain by a disulphide bond. The epsilon chain is present in trace amounts. The two other chains, beta and gamma, differ by their C-terminal amino acid, which is respectively arginine and lysine. 3. Inhibitor is composed of the last 92 or 89 residues of the human albumin molecule and fragment F1 is composed of two parts of this C-terminal portion of the albumin molecule.
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PMID:Chemical structure of two fragments of human serum albumin and their location in the albumin molecule. 116 60

Glucosaminephosphate synthase (glucosaminephosphate isomerase (glutamine-forming), EC 5.3.1.19) prepared from rat liver by extraction in the presence of glucose 6-phosphate (Glc-6-P) followed by precipitation with (NH4)2SO4 is susceptible to digestion by trypsin. This enzyme, designated form A, can be converted to tryptic-insusceptible form B upon incubation with Glc-6-P or fructose 6-phosphate (Fru-6-P) at 37 degrees C. The two forms also differ in the degree of activation by dithiothreitol, the degree of inhibition by methyl-glyoxal and the behavior on DEAE-Sephadex and Sephadex G-200 column chromatography. During purification with DEAE-Sephadex followed by hydroxyapatite, form B is converted to form A if Fru-6-P is absent and form A to form B if Fru-6-P is present. The two forms are therefore intercovertible. Under the conditions of purification, form B is more stable than form A, since the purity and yield of the final product are greater with form B than with form A. These findings suggest that the two forms of glucosaminephosphate synthase differ conformationally and that the equilibrium position depends on the concentration of Fru-6-P. Glc-6-P is effective only when it gives rise to Fru-6-P by mediation of glucose-phosphate isomerase.
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PMID:Stabilization of glucosaminephosphate synthase from rat liver by hexose 6-phosphates. Properties and interconversion of two molecular forms. 124 93

Although human liver contains glucosaminephosphate synthase (glucosaminephosphate isomerase (glutamine-forming), EC 5.3.1.19), its activity is rapidly lost during the course of extraction. The inactivation, however, is largely prevented if the extraction medium contains isopropanol at 1% concentration; using these "stabilized" extracts, the glucosaminephosphate synthase activity of human liver has been shown to be similar to the activity previously reported in rat liver. The enzyme precipitated from these extracts by (NH4)2SO4 is inhibited by UDP-N-acetylglucosamine, the concentration required to produce a half-maximal inhibition being 6 muM. These results seem to be sufficient to postulate that glucosaminephosphate synthase is important for UDP-N-acetylglucosamine synthesis in human liver. In contrast to the rat liver enzyme, the (NH4)2SO4-precipitated human liver enzyme is resistant to trypsin and undergoes no conversion reaction when incubated with glucose 6-phosphate.
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PMID:Glucosaminephosphate synthase of human liver. 124 94


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