Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

35Cl minus-nuclear magnetic resonance (NMR) studies indicate that various digests of human hemoglobin with carboxypeptidase A and B, or a combination of the two, may be used for the identification of chloride binding sites. All the digestion products contain, like hemoglobin itself, at least two classes of binding sites, one of high, the others of low affinity. The pH dependence of the excess linewidth of the 35Cl minus NMR signal indicates that in the simple digests with either carboxypeptidase A or B, chloride is bound with high affinity at or near His-beta146-Asp-beta94 and at or near Val-alpha1-Arg-alpha141. The high-affinity sites show, in the case of the simple digests, a strong oxygen linkage which is lost in the forms digested with both carboxypeptidase A and B; this linkage may thus be correlated to the presence of conformational changes. Organic phosphates, like inositol hexaphosphate, show competition for some of the high-affinity chloride binding sites in hemoglobin and in the simple digests. This competition is likewise lost in the doubly digested hemoglobins.
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PMID:Identification of chloride-binding sites in hemoglobin by nuclear-magnetic-resonance quadrupole-relaxation studies of hemoglobin digests. 0 Feb 36

The reactions between yeast carboxypeptidase C and the group-specific reagents, phenylglyoxal and iodoacetamide, have been studied in detail and the reactions of residue at the active site with N-tosyl-L-phenylalanine chloromethyl ketone and diisopropyl phosphorofluoridate have been confirmed. Modification of the enzyme by either phenylglyoxal or iodoacetamide results in the loss of peptidase activity, while esterase activity remains unchanged. Inactivation by phenylglyoxal appears to be the result of the modification of a single arginine residue, whereas inhibition by iodoacetamide can be correlated with the modification of a single methionine residue. Inactivation of the enzyme by either N-tosyl-L-phenylalanine chloromethyl ketone or diisopropyl phosphorofluoridate is the result of the modification of a single histidine and a single serine residue, respectively. The pattern of inhibition indicates certain analogies in the mechanism of yeast carboxypeptidase C to pancreatic chymotrypsin, on the one hand, and to carboxypeptidase A, on the other.
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PMID:Reaction of yeast carboxypeptidase C1 with group-specific reagents. 1 Sep 62

A mass spectrometric method was developed to determine pH-dependent hydrogen-deuterium exchange at the C-2 position of the imidazole ring of histidine, after converting the amino acid to the methylthiohydantoin derivative. The amount of deuterium exchange in N-acetyl-histidine estimated by the present method was confirmed to be in good agreement with that determined by NMR spectrometry. N-Acetylhistidine was deuterated at various pH's. From the amount of deuterium exchange, a pseudo-first order rate constant (kpsi) was calculated. A pKa value of 7.2 for the amino acid was obtained from the relation between kpsi and pH. This method was applied to estimate the pKa value of beta-146 histidine in human hemoglobin. Human hemoglobin deuterated at various pH's was digested with carboxypeptidase A [EC 3.4.12.2] to release the beta-146 histidine. The amount of deuterium exchange in the isolated histidine was determined to obtain kpsi. From these measurements pKa values of 7.0 for the histidine in oxyhemoglobin and of 8.2 for that in deoxyhemoglobin were found at 36.5 degrees, respectively.
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PMID:Studies on the heterotropic interaction of hemoglobin. I. Mass spectrometric method for determination of the pKa of the beta-146 histidine residue in human hemoglobin. 1 48

1. A colorimetric method was developed for the direct chemical assay of human carboxypeptidase A (carboxypolypeptidase; EC 3.4.12.2) with angiotensin converting enzyme-like activity in serum or plasma, with the substrate analogue glycyl-L-histidylglycine and the angiotensin converting enzyme substrate angiotensin I (A-I). This method was based on the spectrophototometric determination of histidylglycine and histidyl-leucine, products of the hydrolysis of glycyl-L-histidylglycine and A-I respectively. omicron-Phthalaldehyde reacted with the imidazole moiety of nu-terminal histidyl peptides to produce a yellow chromophore. 2. A large number of inhibitors were tested for their effects on carboxypolpeptidase activity. The hydrolysis of Gly-His-Gly and A-I was inhibited by histidyl-leucine and angiotensin II, both products of the hydrolysis of A-I. Bothrops jararaca venom extract, EDTA, rho-chloromercuribenzoate, 8-hydroxyquinoline and 2,3-dimercaptopropanol, previously reported as converting enzyme inhibitors, also inhibited carboxypolypeptidase activity. 3. Angiotensin converting enzyme activity in the serum of sixty-six adults ranged from 10 to 37 nmol of glycyl-L-histidylglygine hydrolysed in 10 min by 10 mu1 of serum at 37 degrees C and pH 7-25.
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PMID:The spectrophotometric determination of human serum carboxypolypeptidase with angiotensin converting enzyme-like activity. 17 49

The possible role of histidine residues in the catalytic function of carboxypeptidase Y from bakers' yeast has been investigated using site-specific reagents. Among the reagents tested, benzyloxy-L-phenylalanylchloromethane (Z-PheCH2Cl) was the most powerful inhibitor of the enzyme. It irreversibly inactivated both the peptidase and esterase activities with an apparent second order rate constant of 3.8 M-minus 1 S-minus 1; the D isomer caused essentially no effect on either activity. Inhibition by L-Z-PheCH2Cl, the reaction retarded by certain competitive inhibitors of the enzyme. Using radioactive L-Z-PheCH2Cl, the reaction with the enzyme was shown to be essentially stoichiometric. Diisopropylphosphorofluoridate (iPr2PF)-inactivated enzyme failed to react with Z-PheCH2Cl, and conversely, the Z-PheCH2Cl-inhibited enzyme failed to react with radioactive iPr2PF. Amino acid analyses of the Z-PheCH2Cl-inactivated enzyme revealed the loss of essentially 1 residue, with a concomitant yield of a 0.62 residue of N-t-carboxymethylhistidine. Since carboxypeptidase Y has a reactive serine at its active center, we concluded from these results that the mechanism involves a charge-relay system in the hydrolysis of peptide and ester substrates, as in chymotrypsin. An -SH group of carboxypeptidase Y was not affected during the reaction with L-Z-PheCH2Cl. The generic name "serine carboxypeptidase" has been proposed for carboxypeptidase Y and for the iPr2PF-sensitive carboxypeptidases from plants, molds, and animal tissues, in order to distinguish them from "metal carboxypeptidase" to which carboxypeptidase A (EC 3.4.12.2) and B (EC 3.4.12.3) belong.
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PMID:Evidence for an essential histidine in carboxypeptidase Y. Reaction with the chloromethyl ketone derivative of benzyloxycarbonyl-L-phenylalanine. 23 80

Mating factor is a peptide excreted into the culture fluid by alpha-mating type cells of Saccharomyces cerevisiae X-2180 1B. The purification of the mating factor was carried out by ion exchange chromatography on phosphocellulose and Amberlite IRC 50 columns, followed by gel filtration on a Sephadex LH 20 column. The factor thus prepared was a peptide composed of Lys1, His1, Trp2, Gln2, Pro2, Gly1, Met1, Leu2 and Tyr1, and was able to induce morphological changes on alpha-mating type cells at a concentration of 5 pg/ml. The amino acid sequence of the mating factor was determined by the manual Edman degradation method using intact mating factor and its thermolytic peptides. The C-terminal amino acid residue was determined by digesting the factor with carboxypeptidase A. The complete amino acid sequence of the mating factor was established to be as follows: Trp-His-Trp-Leu-Gln-Leu-Lys-Pro-Gly-Gln-Pro-Met-Tyr.
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PMID:Purification and amino acid sequence of mating factor from Saccharomyces cerevisiae. 34 Apr 52

A rapid purification procedure for large scale preparations of yeast proteinase B inhibitors 1 and 2 (IB1 and IB2) is described. By disc gel electrophoresis, amino acid analysis, and end-group determinations, each of the inhibitors is homogeneous. Both inhibitors are polypeptides with molecular weights of 8,500, containing 74 residues. No components other than amino acids could be detected. There is no significant difference in the amino acid compositions of the two inhibitors as analyzed after acid hydrolysis. Both polypeptides are characterized by the total absence of arginine, tryptophan, and sulfur-containing amino acid residues. The proteinase B inhibitors of yeast, therefore, differ fundamentally from proteinase inhibitors of many other organisms, which generally contain a large number of disulfide bridges. Both proteinase B inhibitors have threonine as the NH2-terminal residue and -Val-His-Thr-Asn-COO- as the COOH-terminal sequence. Comparison of peptide maps after tryptic digestion reveals that the two inhibitors differ definitely in only a few tryptic peptides. The inhibitors are rapidly inactivated by digestion with carboxypeptidase A from bovine pancreas at pH 8.5. Inactivation occurs stoichiometrically with the release of threonine, the penultimate residue at the COOH-terminal end of both inhibitors.
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PMID:Purification and molecular characterization of two inhibitors of yeast proteinase B. 38 8

The residues 90-92 can be split off from the C-terminal region of the isolated alpha-subunit of choriogonadotropin (residues 88--92: -Tyr-Tyr-His-Lys-Ser-OH) by means of serine carboxypeptidase (des-Lys91,Ser92-alpha-subunit; des-(90-92)-alpha-subunit). However, when choriogonadotropin is digested by serine carboxypeptidase, only the residues 143-145 (-Leu-Pro-Gln-OH) form the C-terminus of the beta-subunit are released (des-(143-145)-choriogonadotropin). Depending on the pH conditions, glutamine 145 and the residues 143-145, respectively, are liberated by digestion of the isolated beta-subunit (des-Gln145-beta-subunit and des-(143-145)-beta-subunit, respectively). The present study provides evidence that the C-termini of both the isolated subunits and those in choriogonadotropin are probably arranged on the surface of the molecules. The biological activity of des-(143-145)-choriogonadotropin is not significantly decreased. The immunological activity, however, is reduced when measured by complement fixation. In comparison to the native hormone, a four-fold amount of des-(143-145)-choriogonadotropin has to be applied to obtain highest complement fixation. The conformation of des-(143-145)-choriogonadotropin does not seem to differ from that of the native hormone, when estimated both by CD measurements and by Ans-choriogonadotropin fluorescence. The respective determinant therefore seems to depend, at least to some extent, on the sequence of the C-terminal region of the beta-subunit of the hormone; complement fixation, however, does not seem to be affected significantly, when the des-(143-145)-beta-subunit is compared with the native beta-subunit using an antiserum against the native beta-subunit. This provides evidence that this C-terminal determinant is possibly more immunogenic at the hormone than at the isolated beta-subunit. The biological activity of recombined choriogonadotropin in vivo as well as in vitro is markedly reduced when serine 92 is removed from the C-terminus of the alpha-subunit (des-Ser92,Lys91-alpha-native beta-subunit: 36% residual activity in vivo). Biological activity is lost when the residues 88-90 are removed by digestion of the des-Ser92,Lys91-alpha-subunit with carboxypeptidase A. Recombination products between a modified alpha-and the native beta-subunit show a reduced Anschoriogonadotropin fluorescence (des-Lys91,-Ser92-alpha + native beta-subunit: 52%; des-(88-92)-alpha- + native beta-subunit: 23%). The Ans-induced aggregation of choriogonadotropin, however, also takes place in those recombination products which display a low Ans-choriogonadotropin fluorescence, indicating that the reduction is probably not caused by a portion of the molecules losing their binding sites for Ans. Therefore the diminished Ans-choriogonadotropin fluorescence seems to signal small conformational changes. The CD spectra of the native and the des-(90-92)-alpha-subunit, however, seem not to differ significantly. It is shown that the release of amino acids from the C-terminus of the alpha-subunit causes a disturbance of the interaction between the subunits. This seems to prevent an effective conformational change of the beta-subunit which probably is a prerequisite for the binding of the hormone to the receptors of Leydig cells.
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PMID:Studies of the specific role of the subunits of choriogonadotropin for biological, immunological and physical properties of the hormone. Digestion of choriogonadotropin and its isolated subunits with serine carboxypeptidase. 52 40

The hemoglobin of the flatworm Dicrocoelium dendriticum, a lanceolate fluke which infests the hepatic ducts of certain mammals, has been isolated by gel filtration and ion-exchange chromatography. The molecular weight of the denatured protein was found to be 15500, a value in the same range as hemoglobin subunits. The fact that the native hemoglobin has an apparent molecular weight of 22000 in 0.01 M phosphate buffer, pH 7.4, suggests limited aggregation. The protein contains, as all other myoglobins and hemoglobins, one molecule of non-covalently associated ferroprotoporphyrin IX per polypeptide chain. It forms the same ligand derivatives with very similar spectral properties as vertebrate hemoglobins. The high oxygen affinity (p50 is 0.07--0.1 mmHg or 9.3--13.3 Pa at 20 degrees C and pH 7.0) and the absence of heme-heme interaction of (Hill coefficient nH=1.0) are properties which this heme protein shares with other monomeric hemoglobins from invertebrate and lower vertebrate organisms. The native hemoglobin exists in two forms, having isoelectric points of 4.51 and 4.53, which do not differ in their amino-acid compositions. Dansylation indicated that the amino-terminal amino-acid residue is alanine. The carboxy-terminal sequence, determined by carboxypeptidase A digestion of the globin, is -His-Ala-Leu.
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PMID:Isolation and characterization of the hemoglobin from the lanceolate fluke Dicrocoelium dendriticum. 68 24

In an attempt to understand the role of nickel in jack bean urease (1), we turned to a variety of other enzymes important in the utilization, production, or transfer of ammonia. We found several, including the L-histidine and L-phenylalanine ammonialyases and some enzymes that utilize glutamine or ammonia in amidotransferase reactions, all of which show evidence for the involvement of as yet unreported transition metal ions in their mechanism of action. We support the view that catalysis by metalloenzymes may be a reflection of the chemistry of the metal ion itself as a Lewis acid, and that perhaps too much emphasis has been placed on supposed special characteristics (such as strains, "entasis") of the enzyme-metal ion association. In this context, we have discussed the mechanism of catalysis of hydrolysis of specific substrates by carboxypeptidase A, and have returned to urease to examine the role of nickel in its mechanism of action.
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PMID:Metal ions in enzymes using ammonia or amides. 76 57


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