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)

From a consideration of (varphi, Psi) values of the amino acids of myoglobin, lysozyme, the alpha and beta chains of horse oxyhemoglobin, tosyl-alpha-chymotrypsin, and carboxypeptidase A, an empirical procedure of predicting whether amino-acid residues in proteins are in a non-helical or may be in a helical conformation has been developed. The conformation of an amino acid at any position n is considered to be influenced by its nearest neighbors (the amino acids at positions n + 1 and n - 1), and the (varphi, Psi) values of the middle amino acid n for the various tripeptide sequences in the known proteins are tabulated. If helical, the (varphi, Psi) values are plotted to define a helical (varphi, Psi) domain. A 20 x 20 table for all tripeptides (n - 1)-(n)-(n + 1) taken sequentially for the entire chain was constructed; it lists the number of instances in which helical and non-helical conformations for the amino acids at position n were found. Certain sequences are found to be associated exclusively with non-helical and others exclusively with helical conformations, whereas many sequences may be either helical or non-helical. The distribution of non-helical residues serves to limit stretches of permissively helical regions; these are then further examined by the helical wheel method. As applied to cytochrome c from 18 species, the only permissively helical segment found was the stretch 91-101 near the C-terminus. For the variable regions of three light and three heavy chains of immunoglobulins, upper limits of 12 and 17% alpha-helix, respectively, were obtained.
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PMID:An attempt to locate the non-helical and permissively helical sequences of proteins: application to the variable regions of immunoglobulin light and heavy chains. 410 30

1. Crystalline myoglobin was isolated from the skeletal muscle of the finback whale and fractionated, in its cyanmet form, into nine components (I-IX) by chromatography on CM-cellulose. Also in the cyanmet form, it was resolved into six components by electrophoresis on starch gel. Correspondence between the electrophoretic and chromatographic components was determined, and interconversion between components revealed by chromatography and electrophoresis. 2. The chromatographic myoglobin components were homogeneous in the ultra-centrifuge. Molecular weights of certain components were determined by means of sedimentation equilibrium and by gel filtration on Sephadex G-100. Values from these two methods corresponded to the minimum molecular weight calculated from the iron content. 3. The spectral properties of the chromatographic components were investigated in the visible and the ultraviolet ranges. 4. The major components of finback-whale myoglobin and sperm-whale myoglobin showed almost identical spectral, electrophoretic and chromatographic behaviours, but had different infrared spectra. The infrared spectra of the corresponding apoproteins were almost identical. 5. Rabbit antisera to sperm-whale myoglobin component X cross-reacted with finback-whale myoglobin components V, VI and VII only about 30%. 6. The major chromatographic components of finback-whale myoglobin have identical amino acid compositions. The polypeptide chain contains 151 amino acid residues and its molecular weight is 17504. 7. The N-terminal end of the chain is: [Formula: see text] Amino acids released from myoglobin by the action of carboxypeptidase A at different intervals were determined.
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PMID:Studies on myoglobin from the finback whale (Balaenoptera physalus). Preparation, physicochemical and immunochemical characterization, differentiation from sperm-whale myoglobin, amino acid composition and end-terminal analyses. 495 75

To enhance the already high quality of diffraction data for crystals of the hydrophobic protein crambin, X-ray data were collected at 130 K by the method of H. Hope to 0.83 A resolution. Refinement with PROLSQ yields a model with an R value of 10.5%. The final model had three parameter anisotropic vibration factors for all atoms, which included 367 protein heavy atoms, 372 hydrogen atoms and 144 solvent atoms with one ethanol molecule. Dihedral angles and hydrogen-bonding distances generally agree with earlier studies of high-resolution protein structures, but some new patterns are noted. Solvent-related helix distortions are reminiscent of those described by others. Helix and beta-sheet regions show distinct patterns in their side-chain conformations. Despite crambin's hydrophobic nature, its accessible surface area in the crystal is surprisingly close to that of water-soluble proteins like myoglobin and carboxypeptidase A. More of crambin's hydrophobic surface is buried in the crystal, perhaps accounting for its high order of diffraction. A total of 24% of the 46 residues show discrete disorder at 130 K. This includes five side-chains at both 300 and 130 K, and six more side-chains and an ethanol molecule at 130 K. Disorder is associated with the sequence microheterogeneity at Pro/Ser22 and Leu/Ile25, with space filling or with solvent disorder. Correlated conformations extend over three to five residues. The patterns of disorder in this structure reveal important principles of protein structure and its dynamics. Finding disordered groups correlated over 5 to 8 A suggests that co-ordinated motion extends in groups rather than simply as uncorrelated movement around an atom center. Thermal diffuse scattering experiments on insulin and lysozyme are consistent with this interpretation. Nearly all of the protein-bound solvent has been located. Less than 1% of protein accessible surface area remains uncovered by solvent or crystal contacts. Preliminary analysis of the solvent network reveals two main networks in each of four solvent regions.
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PMID:Atomic resolution (0.83 A) crystal structure of the hydrophobic protein crambin at 130 K. 845 May 43

Fractions of three trypsin-like proteinases, TL I, TL II, and TL III, a chymotrypsin-like proteinase, CL, two carboxypeptidase A enzymes, CPA I and CPA II and two carboxypeptidase B enzymes, CPB I and CPB II, from Antarctic krill (Euphausia superba) have been characterized with respect to purity by the means of capillary electrophoresis, CE, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The masses of the trypsin-like and chymotrypsin-like proteinases were determined to be 25,020, 25,070, 25,060, and 26,260Da for TL I, TL II, TL III, and CL, respectively. The masses of the CPA enzymes are likely 23,170 and 23,260Da, whereas the CPB enzyme masses likely are 33,730 and 33,900Da. The degradation efficiency and cleavage pattern of the trypsin-like proteinases were studied with native myoglobin as a model substrate using CE, MALDI-TOF-MS, and nanoelectrospray mass spectrometry (nESI-MS). The degradation efficiency of the trypsin-like proteinases was found to be approximately 12 and 60 times higher compared to bovine trypsin at 37 degrees C and 1-3 degrees C, respectively. All three fractions of trypsin-like proteinases showed a carboxypeptidase activity in combination with their trypsin activity.
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PMID:Characterization of proteinases from Antarctic krill (Euphausia superba). 1235 83

Tryptase is a neutral protease of human mast cells, and an important indicator of mast cell activation and degranulation in anaphylactic events. The elevation of serum mast cell tryptase (SMCT) is used for postmortem diagnosis of anaphylaxis. We have quantified the SMCT levels of 122 forensic autopsy cases with various causes of death and found only three where the SMCT levels were remarkably elevated, with values of 179, 68.9 and 69.4 ng/ml (normal level <13.5 ng/ml). The three cases were suspected to have suffered from hyperthermia, and the deaths did not seem to be related to causes of death where SMCT levels have been reported to be elevated in some cases. Two cases were patients who had been prescribed long-term neuroleptics or antidepressants, and myoglobin was detected immunohistochemically in the renal tubules of both cases. The other case died of heatstroke. A possible mechanism of hyperthermia in SMCT elevation is discussed.
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PMID:Three cases of suspected hyperthermia with remarkable elevation of serum mast cell tryptase. 1573 10

To design artificial proteases that cleave peptide backbones of a wide range of proteins at selected sites, artificial active sites comprising the Cu(II) complex of cyclen (Cu(II)Cyc) and aldehyde group were synthesized on a cross-linked polystyrene. The aldehyde group was employed as the binding site in view of its ability of reversible formation of imine bonds with epsilon-amino groups of Lys residues exposed on the surface of proteins and Cu(II)Cyc as the catalytic group for peptide hydrolysis. The two polymeric artificial metalloproteases synthesized in the present study cleaved all of the protein substrates examined (myoglobin, gamma-globulin, bovine serum albumin, human serum albumin, lysozyme, and ovalbumin), manifesting saturation kinetic behavior. At 50 degrees C and pH 9.0 or 9.5, K(m) was (1.3-22) x 10(-)(4) M, comparable to those of natural proteases, and k(cat) was (6.0-25) x 10(-)(4) s(-)(1), corresponding to half-lives of 4.6-19 min. Intermediacy of the imine complexes formed between the aldehyde group of the catalyst and the epsilon-amino groups of Lys residues of the substrates was confirmed by the trapping experiment with NaB(OAc)(3)H. MALDI-TOF MS of the proteolytic reaction mixtures revealed formation of various cleavage products. Structures of some of the cleavage products were determined by using carboxypeptidase A and trypsin. Among various cleavage sites thus identified, Gln(91)-Ser(92) and Ala(94)-Thr(95) were the major initial cleavage sites in the degradation of myoglobin by the two catalysts. The selective cleavage of Gln(91)-Ser(92) and Ala(94)-Thr(95) was attributed to general acid assistance in peptide cleavage by Tyr(146) located in proximity to the two peptide bonds. Broad substrate selectivity, high cleavage-site selectivity, and high proteolytic rate are achieved, therefore, by positioning the aldehyde group in proximity to Cu(II)Cyc attached to a cross-linked polystyrene.
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PMID:Artificial metalloprotease with active site comprising aldehyde group and Cu(II)cyclen complex. 1598 87