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)

The neutral histidine-rich polypeptide (HRP) from human parotid secretion was isolated by ion-exchange and gel-filtration chromatography. The complete amino acid sequence determined by automated Edman degradation of the protein, tryptic and Staphylococcus aureus V8 protease peptides, and digestion with carboxypeptidase A is: (Formula: see text) where Pse represents phosphoserine. The polypeptide contains 38 residues and has Mr 4929. The charged amino acids predominate with 7 histidine, 4 arginine, 3 lysine, 3 aspartic acid, 3 glutamic acid residues, and 1 phosphoserine. Assuming minimal charge contributions from histidine and one negative charge from phosphoserine at pH 7, the net charge of HRP is balanced by an equal contribution of basic and acidic residues. Furthermore, the distribution of hydrophilic and hydrophobic residues along the polypeptide chain indicates that there is no structural polarity. The polypeptide lacks threonine, alanine, valine, cysteine, methionine, and isoleucine. HRP did not display sequence similarity with any protein sequence in the National Biomedical Research Foundation Data Bank. HRP is an active inhibitor of hydroxyapatite crystal growth from solutions supersaturated with respect to calcium phosphate salts and therefore must play a role in the stabilization of mineral-solute interactions in oral fluid. In addition, HRP is a potent inhibitor of Candida albicans germination and therefore may be a significant component of the antimicrobial host defense system in the oral cavity.
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PMID:The primary structure and functional characterization of the neutral histidine-rich polypeptide from human parotid secretion. 394 83

We have utilized a highly sensitive radiationless energy transfer (RET) assay to investigate the effect of anions on the activity of carboxypeptidase A (CPD-A). The RET kinetic method visualizes the ES complex directly and thus enables both the mode of action of anions and the quantitation of their effect to be determined at a single substrate concentration. In marked contrast to the activating effect of anions on the closely related metalloprotease, angiotensin converting enzyme, Cl-, and other anions inhibit CPD-A catalysis. NaCl inhibits the hydrolysis of Dns-Ala-Ala-Phe throughout the pH range 6-10. Other di- and tripeptides are similarly inhibited while their ester analogues are affected only slightly. Changes in the type of cation [e.g., Na+, Li+, K+, Ca2+, and (CH3)4N+] at a constant [Cl-1] of 0.1 M showed no difference in the extent of inhibition, whereas with anion substitution the differences were marked. In all cases, the inhibition was partially competitive. At pH 5.9, the Ki values for the free enzyme are 51 (Cl-), 17 (N3-), 2.1 (SO4(2-)), and 0.21 mM (H2PO4-), and for the ES complex, the KI' values are 1000, 720, 42, and 13 mM, respectively. The other anions were shown to act at the chloride site. The results indicate that investigations of anion inhibition in 1 M NaCl, a typical assay condition, may be greatly hindered by the presence of Cl-. Thus, the competitive binding mode of phenylacetate toward peptide hydrolysis is greatly decreased by the presence of 1 M Cl- ion while its noncompetitive component is unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Kinetic analysis by stopped-flow radiationless energy transfer studies: effect of anions on the activity of carboxypeptidase A. 395 97

Adipokinetic hormones II from corpora cardiaca of the locusts Schistocerca gregaria and Locusta migratoria, respectively, have been isolated and their primary structures elucidated. Both octapeptides are N-terminally blocked by a 5-oxoproline (pyroglutamate) residue and had to be cleaved by 5-oxoprolyl-peptidase to make them available for the Edman degradation method carried out with a gas-phase sequencer. The C-termini are blocked as both peptides are not cleaved by carboxypeptidase A; the presence of C-terminal amide groups is very likely. AKHII (S. gregaria) Glu-Leu-Asn-Phe-Ser-Thr-Gly-Trp-NH2 AKHII (L. migratoria) Glu-Leu-Asn-Phe-Ser-Ala-Gly-Trp-NH2.
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PMID:Primary structures of locust adipokinetic hormones II. 406 72

Ribosomal proteins were isolated from logarithmically growing Escherichia coli cells given [(14)C]alanine for short periods. Surprisingly, the specific activity of alanine at the NH(2)-terminal end was higher than that of alanine released by carboxypeptidase A digestion of the ribosomal protein. To determine the direction of chain elongation more precisely, Escherichia coli cells were grown with [(3)H]amino acids, and [(14)C]amino acids were then given to the (3)H-labeled cells as a pulse. Radioactive 30S ribosomal proteins were isolated from these cells and subjected to carboxypeptidase digestion. The ratio of (14)C to (3)H of the released amino acids increased as the time for carboxypeptidase digestion progressed. These observations suggest that some of the ribosomal proteins may be synthesized from the carboxyl end to the amino end through a novel mechanism.
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PMID:Direction of chain elongation in the formation of Escherichia coli ribosomal protein. 527 82

1. Urease of specific activity 160-180 Sumner units/g. (Sumner, 1951) was purified from jack-bean meal. The preparation was pure on the basis of polyacryl-amide-gel electrophoresis and N-terminal studies. 2. By using both the 1-fluoro-2,4-dinitrobenzene method and the phenyl isothiocyanate method a single N-terminal methionine residue was found. 3. A single C-terminal sequence -Tyr-Leu-Phe was found by studies with carboxypeptidase A, carboxypeptidase B and hydrazinolysis. 4. N-Bromosuccinimide cleavage showed that five unique tryptophan sequences were present: Trp-Ala, Trp-Glu, Trp-Gly, Trp-Met and Trp-Arg. 5. Polyacrylamide-gel electrophoresis in sodium dodecyl sulphate showed that urease had a subunit molecular weight of 76000. 6. The yield of N- and C-terminal amino acids, the number of tryptic peptides and tryptophan sequences and the above polyacrylamide-gel electrophoretic measurement all suggest that urease contains a single structural subunit of molecular weight 75000.
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PMID:The subunit structure of jack-bean urease. 538 87

p6gestibility by proteolytic enzymes of peptides cross-linked by ionizing radiation was investigated. Small peptides of alanine and phenylalanine were chosen as model compounds and aminopeptidases and carboxypeptidases were used as proteolytic enzymes. Peptides exposed to gamma-radiation in aqueous solution were analysed by high-performance liquid chromatography before and after hydrolysis by aminopeptidase M, leucine aminopeptidase, carboxypeptidase A and carboxypeptidase Y. The results obtained clearly demonstrate the different actions of these enzymes on cross-linked aliphatic and aromatic peptides. Peptide bonds of cross-linked dipeptides of alanine were completely resistant to enzymatic hydrolysis whereas the enzymes, except for carboxypeptidase Y, cleaved all peptide bonds of cross-linked peptides of phenylalanine. The actions of the enzymes on these particular compounds are discussed in detail.
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PMID:Enzymatic digestibility of peptides cross-linked by ionizing radiation. 614 37

Comparative studies of the activity of somatostatin and of several of its analogues in releasing histamine from rat mast cells suggest that the integrity of the positively charged amino terminus and of lysines at positions four and nine of somatostatin may be necessary to preserve its histamine releasing activity. D-Lys4 substitution reduced activity by 80% while D-Lys9 substitution increased it four fold. Replacement of the amino terminal Ala by Tyr or simultaneous removal of Ala1,Gly2 and the amino portion of the now terminal Cys3 inhibited the activity by about 95%. Finally, dihydrosomatostatin retained 33% activity while an analogue where both Cys sulfur atoms were permanently blocked by acetamidomethyl groups retained only about 13% activity. Using information from these studies and from the literature, two-dimensional and space-filling models approximating the conformation of somatostatin were constructed and compared with a plausible corresponding model of the hexameric form of 48/80, the most active congener of this classic mast cell secretagogue. By such modelling it was possible to show that the orientation of the cationic moieties in the two molecules could be similarly arranged thereby perhaps explaining the ability of these compounds to induce mast cell secretion.
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PMID:Mast cell histamine secretion in response to somatostatin analogues: structural considerations. 617 34

Two peptides rich in hydrophobic amino acids have been isolated from venom sacs of the European hornet, Vespa crabro. One peptide (P-2) is structurally and functionally related to the tetradecapeptide mastoparan and has been named mastoparan C. Leu-Asn-Leu-Lys-Ala-Leu-Leu-Ala-Val-Ala-Lys-Lys-Ile-LeuNH2. The other (P-1) is a tridecapeptide with a new sequence: Phe-Leu-Pro-Leu-Ile-Leu-Arg-Lys-Ile-Val-Thr-Ala-LeuNH2 which we have named crabrolin. The peptide releases histamine from rat peritoneal mast cells with a threshold of approximately 2.5 micrograms/ml (congruent to 8 microM). Crabrolin also facilitates the action of purified phospholipase A2 from different sources, but it is not quite as active as mastoparan. It is clearly less active than mastoparan in lysing erythrocytes, and it does not release amylase from dispersed guinea pig pancreatic acini. Given its unique sequence, the principal effect of crabrolin may be neither mast cell degranulation nor phospholipase facilitation, but a yet undiscovered action.
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PMID:Isolation and characterization of two new peptides, mastoparan C and crabrolin, from the venom of the European hornet, Vespa crabro. 620 53

Penicillinase from Bacillus cereus 569/H was purified to homogeneity. Its active site was probed by use of an affinity label generated in situ by the diazotization of 6-aminopenicillanic acid, a catalytically poor substrate for this enzyme. The loss of activity arising during the inactivation is dependent upon pH and the penicillin:sodium nitrite ratio used. Optimal inactivation was obtained at pH 4.7 and reactivation could be prevented if subsequent purification and manipulations were performed at low pH. Inactivation by diazotized 6-aminopenicillanic acid was characterized further by tryptic and chymotryptic digestion of the inactivated enzyme and peptide mapping of the resulting digests. Amino acid analysis of the chymotryptic labeled peptide yielded a composition which corresponds to residues 41-46 (Ala-Phe-Ala-Ser-Thr-Tyr) in the published partial sequence of the enzyme (Thatcher, D. (1975) Biochem. J. 147, 313-326). Further digestion of this chymotryptic peptide with carboxypeptidase A reveals that serine-44 is modified in this affinity labeling procedure. Mass spectral analysis of the modified serine residue and alkali-released label, and comparison with spectra of model compounds indicates that the inactivation occurs with rearrangement of the beta-lactamthiazolidine structure to a dihydrothiazine.
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PMID:Bacillus cereus 569/H penicillinase serine-44 acylation by diazotized 6-aminopenicillanic acid. 630 23

Kay and his colleagues [1] have suggested that the neutrophil high molecular weight chemotactic factor ( NCF ) found in the serum of patients suffering from a variety of allergic diseases is mainly derived from mast cells and is therefore an indicator of mast cell activation. We have studied some of the properties of NCF obtained from patients with atopic extrinsic asthma and compared it with N-formyl-1-methionyl-1-leucyl-1-phenyl-alanine (FMLP), a chemotactic peptide [2]. A number of differences between FMLP and NCF were observed. In contrast to FMLP, checkerboard analysis showed that NCF caused random migration of neutrophils. In addition microscopic analysis of neutrophil locomotion in response to FMLP demonstrated the characteristic pseudopod formation. Furthermore, it was found that in contrast to FMLP, NCF did not cause the release of lysosomal enzymes from cytochalasin B-treated neutrophils. These results suggest that NCF has chemokinetic rather than chemotactic properties.
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PMID:Properties of a high molecular weight neutrophil chemotactic factor, possibly derived from mast cells: evidence for chemokinetic rather than chemotactic activity. 637 6


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