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)

Comparison of various chloroplast-type ferredoxin sequences, chemical and enzymic modifications, reconstitution experiments, and fluorescence measurement of chloroplast-type ferredoxins have led to the following conclusions. 1. Tyrosine, histidine, and tryptophan residues are not directly involved in the oxidation-reduction mechanism of ferredoxins. The four indispensible cysteine residues in spinach ferredoxin which constitutes a part of the iron-sulfur cluster are located at residues 39, 44. 47 and 77. Two out of six cysteine residues in Spirulina ferredoxin could be easily modified with vinylpyridine without the loss of reconstitutive ability i.e. the apoferredoxin could be converted to the holoform by the addition of iron and sulfide. 2. Spinach ferredoxin was digested with carboxypeptidase A and the terminal alanine could be removed without loss of the spectral properties of native ferredoxin. However, the removal of the terminal three residues gave rise to the loss of reconstitutive ability. 3. The amino groups of spinach ferredoxin were modified by acetic anhydride and four residues were acetylated. The acetylated preparation of ferredoxin had an unique spectrum. Upon the addition of high concentration of ions the spectrum of this derivative resembled the spectrum of native ferredoxin. Acetylferredoxin did not combine with ferredoxin-NADP reductase, but upon the addition of moderate concentrations of cations, it did bind to this enzyme.
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PMID:Structure and function of chloroplast-type ferredoxins. 78 73

The i.p. administration of L-histidine in doses of 500 and 1000 mg/kg, caused prolonged high levels of histidine but did not influence the levels of histamine in the non-mast cell tissues such as the stomach, lungs and liver in the rat. After polymyxin B or 48/80 treatments as well as in anaphylaxis, the levels of histamine in the lungs and liver were greatly reduced but histidine administration failed to alter noticeably the concentrations of histamine in these organs. Similarly, the low contents of histamine in the stomach of 48/50-treated or polymyxin B-treated rats remained unchanged in the presence of excess histidine. Histidine loadings however produced a marked increase in histidine decarboxylase activity of the glandular stomach and a simultaneous elevation in the serum histamine concentrations. Results suggest that the increased level of serum histamine is the consequence of the increased activity of histidine decarboxylase in the tissues and a rapid elimination of the newly formed histamine into the blood. This led us to consider that the flux rather than the formation of histamine might be regulatory for the actual concentration of the non-mast cell histamine, especially in stomach tissue.
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PMID:Non-mast cell histamine levels in rat tissues after histidine loading. 85 8

The synthesis by conventional methods of the following three peptides is described: MCD(8-11) Boc-His(Trt)-Val-Ile-Lys(Z) (III) MCD(5-7) Boc-Cys(SiPr)-Lys(Z)-Arg(Tos) (IV) and MCD(1-4) Boc-Ile-Lys(Z)-Cys(Trt)-Asn(Mbh) (V). These peptides are fragments of the mast cell degranulating peptide from bee venom. The purity of the fragments synthesized was examined by thin-layer chromatography, amino acid and elementary analysis. Including the fragments Boc-Lys(Z)-Ile-Cys(SiPr)-Gly-Lys(Z) (I) and Boc-Pro-His(Trt)-Ile-Cys(Trt)-Arg(Tos) (II), which were described earlier, the synthesis of the mast-cell-degranulating peptide on a polyethylene-asparagine support appears possible.
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PMID:[Basic peptides in bee venom, III. Synthesis of peptide fragments from the sequence of the mast-cell-degranulating peptide (author's transl)]. 85 9

The NH2- and COOH-terminal sequence of nuclear portein A24 has been determined by automatic Edman degradation and carboxypeptidase A and B digestion. Protein A24 is of interest because it is composed in part of histone 2A (Goldknofp, I.L., and Busch, H., (1975) Biochem, Biophys. Res. Commun. 65, 951-960). The sequence of the first 37 NH2-terminal residues is: Met-Gln-Ile-Phe-Val-Lys-Thr-Leu-Thr-Gly-Lys-Thr-Ile-Thr-Leu-Glu-Val-Glu-Pro-Ser-Asp-Thr-Ile-Glu-Asn-Val-Lys-Ala-Lys-Ile-Gln-Asp-Lys-Glu-Gly-Ile-Pro- This sequence is not homologous to any known histone sequence. It contains regions of internal homology (italics). The COOH-terminal amino acid sequence is the same as that of histone 2A, naely: -His-His-Lys-Ala-Lys-Gly-Lys-COOH.
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PMID:The NH2- and COOH-terminal amino acid sequence of nuclear protein A24. 97 47

Five amino acid residues, i. e. serine, lysine, histidine and two tyrosine residues, are split from the C-end of the alpha-subunit of bovine luteinizing hormone by carboxypeptidase A. Gel-filtration through Sephadex G-100 demonstrated that the carboxypeptidase-treated alpha-subunit is not recombined with the native beta-subunit and does not form complex molecules of the hormone.
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PMID:[Important role of C-terminal amino acid sequence of the luteinizing hormone alpha-subunit in its recombination with the beta-subunit]. 102 94

An asymptomatic woman was found to have a compensated hemolytic state due to an unstable hemoglobin variant, comprising 35% of the total. Peptide maps of tryptic digests of the abnormal beta chain were identical to those of beta A except that tryptic peptide 15 (Tyr-His-COOH) was absent and a new peptide was detected, containing equivalent amounts of Ser, Ile, Thr, and Lys. Its sequence was determined by manual Edman degradation. An additional hydrophobic peptide isolated by counter-current distribution contained: Asx, Ser, Ala, Tyr, 2 Phe, and 3 Leu. Its sequence was determined on an automatic solid phase sequencer. Digestion with carboxypeptidase A confirmed the C-terminal sequence. Hemoglobin Cranston has an elongated beta chain with the following structure: (see article). This variant is the first "adult" human hemoglobin known to contain isoleucine. It is likely that hemoglobin Cranston arose because of a nonhomologous crossover of two normal beta chain genes, probably during meiosis, with the insertion of two nucleotides (AG) at position 144, resulting in a frame shift. Hemoglobin Cranston provides new information on the structure of the beta chain gene as well as an explanation of both the structure and genetic basis of hemoglobin Tak, the only other elongated beta chain variant that has been described.
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PMID:Hemoglobin Cranston, an unstable variant having an elongated beta chain due to nonhomologous crossover between two normal beta chain genes. 105 49

Subcellular fractionation techniques, radio-labeling by the 3H-precursor and pharmacological approach applied to the developing rat indicate the presence of at least two types of histamine-containing cells in brain. The presence of the histamine synthesizing enzyme in neurons is suggested by its developmental pattern: there is a 4- to 5-fold increase in enzyme activity from birth to adulthood, with a time-course paralleling the synaptogenesis in whole brain as well as in the 4 regions studied (medulla-pons, midbrain, hypothalamus and forebrain). As is the case for different transmitter synthesizing enzymes such as tyrosine hydroxylase, there is a shift in the subcellular distribution of histidine decarboxylase (H.D.) activity from the soluble fraction at birth to the synaptosomal fraction in the adult brain. On the other hand, several lines of evidence indicates that a portion of histamine is localized, at least in the noenatal rat brain, in mast cells: (a) the high level of histamine in the neonatal rat brain is, like in peripheral mast-cells, associated with a low enzyme activity; (b) the half-life of [3H]histidine injected s.c. at birth was about 4 days, a value close to that found in skin (a tissue rich in mast cells), but contrasting with that in adult brain (less than 1 h); (c) after subcellular fractionation, the endogenously formed [3H]histamine was recovered in the crude nuclear fraction as was the amine from peritoneal mast cells added to the brain homogenate; (d) the mast cell degranulators, compound 48/80 and polymyxin B, induce a small but significant release of the amine from incubated neonatal brain slices. Thus it appears that cerebral histamine is localized in at least two cell types. Its presence in neurons is compatible with a neurotransmitter function and its release from mast cells might represent some primitive form of cell-to-cell communication.
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PMID:Histamine synthesis in the developing rat brain: evidence for a multiple compartmentation. 110 98

Although optical resolution of alpha-methylphenylalanine (alpha-Me-Phe) has been achieved by the action of carboxypeptidase A on the N-trifluoroacetyl derivative of the amino acid (TFA-alpha-Me-Phe), it is improbable that an alpha-methyl substrate could bind in the same orientation as glycyl-L-tyrosine, due to steric interaction of the alpha-methyl group with an atom in the imidazole ring of zinc ligand His-196. The kinetic parameters for TFA-alpha-Me-Phe and for an ester substrate bearing an alpha-methyl group (beta-hippuryl-alpha-methylphenyllactic acid, HMPL) have been determined and compared to those for the appropriate nonmethylated control substrates. Both TFA-alpha-Me-Phe and HMPL appear to be bound nearly as well as are their respective controls, and HMPL is hydrolyzed nearly as rapidly as its control. TFA-alpha-Me-Phe, however, is hydrolyzed only about one-fiftieth as rapidly as is the nonmethylated substrate. These findings are consistent with the possibilities that: (1) the proposed substrate-induced conformational shift of Tyr-248 is hindered when the methylated substrates are bound; (2) the orientation in which alpha-methyl substrates are bound precludes optimal positioning of Tyr-248 and the scissile bond even after the rotation of Tyr-248 has occurred; (3) amides and esters are bound in different orientations, and in the amide orientation an alpha-methyl group is so directed as to interfere with the approach of Glu-270 to the scissile bond.
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PMID:alpha-Methyl substrates of carboxypeptidase A. A steric probe of the active site. 114 72

The complete covalent structure of a small, basic protein with cardiotoxic activity is described. This has been isolated from the venom of Naja nigricollis by gel filtration on Sephadex G-75 and gradient ion exchange chromatography on Bio-Rex 70. The cardiotoxin, molecular weight 6806 from amino acid composition, consists of 60 amino acids, cross-linked by four disulfide bridges, connecting 3-21, 14-38, 42-53, and 54-59. The protein contains one residue of tryptophan, phenylalanine, and glutamic acid, two residues of arginine and tyrosine, four residues of methionine, and nine residues of lysine. Histidine is absent. The chymotryptic peptides of the oxidized and S-carboxymethylated protein were isolated by gel filtration on Sephadex G-25 and zone electrophoresis on a cellulose column. The sequence was determined by Edman degradation, using the (manual) direct phenylthiohydantoin method and with the use of carboxypeptidase A. Disulfide pairing was determined on thermolysin cleaved peptides from the native protein. The sequence is shown to be homologous to other cardiotoxins and a lytic factor from snake venoms and also shows homology, both in sequence and disulfide pairing to neurotoxins. A partial reduction experiment in the absence of denaturing agent using 14-C-labeled iodoacetic acid as S-carboxymethylating agent shows that disulfide bonds 14-38 and 42-53 were reduced fastest followed marginally by 54-59, and then bond 3-21.
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PMID:The complete covalent structure of a cardiotoxin from the venom of Naja nigricollis (African black-necked spitting cobra). 114 81

1H NMR spectroscopy of the isotropically shifted signals in cobalt carboxypeptidase, CoCPD, permits a direct and selective detection of protons belonging to the residues liganded to the metal. The chemical shift of these protons in the free enzyme and enzyme-inhibitor complexes with changing pH monitors the state of ionization of the ligands directly and of other residues in the active center indirectly. The 1H NMR spectrum of CoCPD at pH 6 shows three well-resolved isotropically shifted signals in the downfield region at 62 (a), 52 (c), and 45 (d) ppm which have been assigned to the NH proton of His-69 and to the C-4 H's of His-69 and His-196, respectively. Titration of signal a with pH is characterized by a pKa of 8.8 which is identical to that seen in prior electronic absorption and kinetic studies. The fact that the signal reflecting the NH of His-69 is still observed at pH 10 and no major shifts occur for the signals reflecting the C-4 H's indicates the alkaline pKa in carboxypeptidase A catalysis, pKEH, cannot be ascribed to ionization of the histidyl NH of either His-69 or His-196. Binding of L-Phe shifts this pKa to 7.7 while not greatly perturbing the downfield 1H NMR signals that reflect the ligation shell of the cobalt coordination sphere. These results indicate the pKa of 8.8 in CoCPD and the pKa of 7.7 in the CoCPD.L-Phe adduct reflect ionization of the same group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:pH-dependent properties of cobalt(II) carboxypeptidase A-inhibitor complexes. 156 40


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