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 orientation of cytochrome b6 in the thylakoid membrane and the question of whether the number of membrane spanning helices is an even or odd number was tested through the relative trypsin susceptibility of epitopes (Asp-5 to Gln-14) and (Ile-205 to Leu-214) at the NH2 and COOH termini, respectively, of the 214-residue cytochrome b6 polypeptide. A structure of the cytochrome with an even number of helices and the NH2 and COOH termini on the stromal side of the membrane was inferred from the following: 1) cleavage of cytochrome b6 by trypsin added to thylakoids occurs by removal of both of the exposed NH2- and COOH-terminal epitopes. The epitopes at the termini were more sensitive to trypsin after prior treatment of thylakoids with carboxypeptidase A, indicating that these epitopes are shielded on the stromal side of the membrane by the COOH termini of other proteins. 2) Both epitopes were more trypsin-sensitive in thylakoid membranes than was cytochrome f that is only sensitive to trypsin acting on the lumen side of the membrane. 3) The NH2- and COOH-terminal epitopes of cytochrome b6 were also more sensitive to trypsin added to thylakoid membranes than were the oxygen-evolving complex 16- and 33-kDa proteins that are completely located on the lumen side. 4) The order of trypsin susceptibility was reversed in inside-out membranes, where the cytochrome NH2- and COOH-terminal epitopes were less sensitive than the 16- and 33-kDa proteins. The decreased relative sensitivity of the cytochrome b6 epitopes occurs in spite of a greater absolute sensitivity of these epitopes to trypsin in inside-out membranes. 5) The greater absolute sensitivity can be explained by a 4-helix model that includes trypsin-sensitive sites on the lumen side.
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PMID:Thylakoid membrane protein topography. Location of the termini of the chloroplast cytochrome b6 on the stromal side of the membrane. 169 78

The inhibitory effect of various dipeptides on the neurotensin-degrading metallopeptidase, endopeptidase 24.16, was examined. These dipeptides mimick the Pro10-Tyr11 bond of neurotensin that is hydrolyzed by endopeptidase 24.16. Among a series of Pro-Xaa dipeptides, the most potent inhibitory effect was elicited by Pro-Ile (Ki approximately 90 microM) with Pro-Ile greater than Pro-Met greater than Pro-Phe. All the Xaa-Tyr dipeptides were unable to inhibit endopeptidase 24.16. The effect of Pro-Ile on several purified peptidases was assessed by means of fluorigenic assays and HPLC analysis. A 5 mM concentration of Pro-Ile does not inhibit endopeptidase 24.11, endopeptidase 24.15, angiotensin-converting enzyme, proline endopeptidase, trypsin, leucine aminopeptidase, pyroglutamyl aminopeptidase I and carboxypeptidase B. The only enzyme that was affected by Pro-Ile was carboxypeptidase A, although it was with a 50-fold lower potency (Ki approximately 5 mM) than for endopeptidase 24.16. By means of fluorimetric substrates with a series of hydrolysing activities, we demonstrate that Pro-Ile can be used as a specific inhibitor of endopeptidase 24.16, even in a complex mixture of peptidase activities such as found in whole rat brain homogenate.
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PMID:Specific inhibition of endopeptidase 24.16 by dipeptides. 176 Oct 32

A new 28 amino acid peptide, we recently isolated from the venom of the bumblebee Megabombus pennsylvanicus. has been characterized. The peptide, Met-Cys-Ile-Cys-Lys-Asn-Gly-Lys-Pro-Leu-Pro-Gly-Phe-Ile-Gly-Lys-Ile-Cys- Arg-Lys-Ile-Cys-Met-Met-Gln-Gln-Thr-His(NH2), has been named bumblebee mast cell degranulating (MCD) peptide due to its ability to degranulate rat peritoneal mast cells, and its resemblance to the bee venom MCD peptide. Bumblebee MCD peptide, unlike bombolitins, the other mast cell degranulating heptadecapeptides of bumblebee venom, is not lytic and releases histamine at a dose as low as 0.05 micrograms/ml (1.6 X 10(-8) M).
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PMID:Amino acid sequence of bumblebee MCD peptide: a new mast cell degranulating peptide from the venom of the bumblebee Megabombus pennsylvanicus. 242 Dec 65

The acid proteases, pepsin, rennin and cathepsin D, were shown to generate mast cell histamine releasing peptides (HRP) when incubated with the albumin fraction of mammalian plasmas. Significant histamine release was observed using less than 1 microliter equivalent of pepsin-treated plasma. Histamine release was rapid, dependent on calcium and energy, and accompanied by degranulation. The major HRP present in pepsin-treated human and canine plasma was identified as H-Ile-Ala-Arg-Arg-His-Pro-Tyr-Phe-OH whereas that from rat plasma had valine substituted for isoleucine. Cathepsin D-treated BSA gave rise to the human octapeptide (above) as well as to an extended decapeptide with H-Tyr-Glu- at the N-terminus. These peptides were apparently derived from one region of serum albumin, residues 139 to 149 of the human, canine, or bovine sequence. We hypothesize that cathepsin D, released from leukocyte lysosomes, might generate HRP during the delayed phase of an inflammatory response.
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PMID:Structures of histamine-releasing peptides formed by the action of acid proteases on mammalian albumin(s). 247 9

Five structurally related heptadecapeptides rich in hydrophobic amino acids have been discovered in the venom of the bumblebee Megabombus pennsylvanicus. We have named them bombolitin I (Ile-Lys-Ile-Thr-Thr-Met-Leu-Ala-Lys-Leu-Gly-Lys-Val-Leu-Ala-His-Val-NH2 ), bombolitin II (Ser-Lys-Ile-Thr-Asp-Ile-Leu-Ala-Lys-Leu-Gly-Lys-Val-Leu-Ala-His-Val-NH2 ), bombolitin III (Ile-Lys-Ile-Met-Asp-Ile-Leu-Ala-Lys-Leu-Gly-Lys-Val-Leu-Ala-His-Val-NH2 ), bombolitin IV (Ile-Asn-Ile-Lys-Asp-Ile-Leu-Ala-Lys-Leu-Val-Lys-Val-Leu-Gly-His-Val-NH2 ), and bombolitin V (Ile-Asn-Val-Leu-Gly-Ile-Leu-Gly-Leu-Leu-Gly-Lys-Ala-Leu-Ser-His-Leu-NH2 ). Bombolitins are structurally and functionally very similar. They lyse erythrocytes and liposomes, release histamine from rat peritoneal mast cells, and stimulate phospholipase A2 from different sources. The threshold dose is 0.5-2.5 micrograms/ml depending on the peptide and the bioassay. Bombolitin V is as potent as the well-known melittin in lysing guinea pig erythrocytes (ED50 = 0.7 microgram/ml = 4 X 10(-7) M) and is 5 times more potent than mastoparan in causing mast cell degranulation, making it one of the most potent degranulating peptides discovered so far (ED50 = 2 micrograms/ml = 1.2 X 10(-6) M). The bombolitins represent a unique structural class of peptides but they have the same biological properties as melittin (from honeybees), mastoparan (wasps, hornets, and yellow jackets), and crabrolin (European hornets). This unusual circumstance (peptides with different amino acid sequences having the same biological properties) may be a manifestion of their amphiphilic nature, a property these peptides have in common.
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PMID:Bombolitins, a new class of mast cell degranulating peptides from the venom of the bumblebee Megabombus pennsylvanicus. 257 59

A novel inhibitor of angiotensin-converting enzyme (ACE) derived from tuna muscle, Pro-Thr-His-Ile-Lys-Trp-Gly-Asp (tuna AI), was chemically synthesized, and its biological properties were investigated. Synthetic tuna AI was found to be chemically and biologically indistinguishable from the native one. Tuna AI inhibited rabbit lung ACE non-competitively with Ki values of 1.7 and 5.7 microM with substrates, hippuryl-L-histidyl-L-leucine and angiotensin I, respectively. This peptide (5.3 microM) also doubled the effect of bradykinin in the contraction of isolated guinea pig ileum. The peptide did not show zinc chelating activity and carboxypeptidase A inhibitory activity. Thus, tuna AI was found to be a unique ACE inhibitory peptide with non-competitive manner, differing from many naturally occurring peptide ACE-inhibitors.
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PMID:Biological properties of angiotensin-converting enzyme inhibitor derived from tuna muscle. 261 45

The stoichiometric complex formed between bovine beta-trypsin and the Cucurbita maxima trypsin inhibitor I (CMTI-I) was crystallized and its X-ray crystal structure determined using Patterson search techniques. Its structure has been crystallographically refined to a final R value of 0.152 (6.0-2.0 A). CMTI-I is of ellipsoidal shape; it lacks helices or beta-sheets, but consists of turns and connecting short polypeptide stretches. The disulfide pairing is CYS-3I-20I, Cys-10I-22I and Cys-16I-28I. According to the polypeptide fold and disulfide connectivity its structure resembles that of the carboxypeptidase A inhibitor from potatoes. Thirteen of the 29 inhibitor residues are in direct contact with trypsin; most of them are in the primary binding segment Val-2I (P4)-Glu-9I (P4') which contains the reactive site bond Arg-5I-Ile-6I and is in a conformation observed also for other serine proteinase inhibitors.
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PMID:The refined 2.0 A X-ray crystal structure of the complex formed between bovine beta-trypsin and CMTI-I, a trypsin inhibitor from squash seeds (Cucurbita maxima). Topological similarity of the squash seed inhibitors with the carboxypeptidase A inhibitor from potatoes. 291 11

A tryptic protease with the characteristics of a mast cell tryptase was purified from dog mastocytoma cells propagated in nude mice. Partial amino acid sequence of the mastocytoma tryptase revealed unexpected differences in comparison with other mast cell and leukocyte granule protease sequences. Extraction from mastocytoma homogenates at high ionic strength, followed by gel filtration and benzamidine affinity chromatography yielded a product with several closely spaced bands (Mr 30,000-32,000) on gel electrophoresis and a single N-terminal sequence. Nondenaturing analytical gel filtration revealed an apparent Mr of 132,000, suggesting noncovalent association as a tetramer. Studies with peptide p-nitroanilides indicated pronounced substrate preferences, with P1 arginine preferred to lysine. Benzoyl-L-Lys-Gly-Arg-p-nitroanilide was the best of the substrates screened. Inhibition by diisopropyl fluorophosphate and tosyllysine chloromethyl ketone indicated that the enzyme is a serine protease. Like the tryptases of human mast cells, mastocytoma tryptic protease was inhibited by NaCl, resistant to inactivation by alpha 1-proteinase inhibitor and plasma, and stabilized by heparin. Comparison of the N-terminal 24 residues of mastocytoma tryptase revealed 80% identity with the more limited sequence reported for human lung tryptase, and surprisingly, closer homology to serine proteases of digestion and clotting than to other leukocyte granule proteases sequenced to date, including mast cell chymase. The N-terminal isoleucine is the homolog of trypsinogen Ile-16 which becomes the new N-terminus upon cleavage of the activation peptide. Thus, the tryptase N-terminus is related to the catalytic domain of activated serine proteases, and lacks the N-terminal regulatory domains found in most clotting and complement serine proteases. These findings provide further evidence that tryptases are unique serine proteases and that they may be less closely related in evolution and function than are other leukocyte granule proteases described to date.
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PMID:Dog mastocytoma tryptase: affinity purification, characterization, and amino-terminal sequence. 311 12

Solitary mastocytoma (mast cell naevus) of the skin represents a relatively rare dermal tumour. Its occurrence on the lower eyelid is exceptional. We report the case of a 4 month old male infant who exhibited a firm, yellowish nodule (1 cm in maximum diameter) on the lower lid of the right eye from birth. Histologically, the tumour consisted of strongly metachromatic tissue mast cells (TMC) infiltrating the whole dermis, the adjacent subcutaneous tissue and the lid muscle. Since comparable skin lesions in other sites were not observed, a diagnosis of solitary mastocytoma was made. Immunocytological investigations revealed strong reactivity of the TMC to antisera against vimentin, common leucocyte antigen (CLA), alpha 1-antitrypsin (alpha 1-AT) and alpha 1-antichymotrypsin (alpha 1-ACT). A minor proportion of the TMC reacted to antisera against lysozyme and KiB3. Surprisingly, the TMC also reacted to antisera against certain regulatory peptides (RP), namely adrenocorticotropic hormone (ACTH), peptide histidine isoleucine (PHI), leu-enkephalin and met-enkephalin. However, absorption controls revealed that the immunostaining for ACTH and the two enkephalins was non-specific. The immunocytological phenotype of TMC suggests a close relationship to the myeloid-monocytic lineage, but a possible relationship between TMC and the diffuse neuroendocrine system needs further investigation.
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PMID:Solitary mastocytoma of the eyelid. A case report with special reference to the immunocytology of human tissue mast cells, and a review of the literature. 312 Apr 1

P401 (also known as mast cell degranulating protein, MCD) is a minor component of honeybee venom. Its primary structure is related to that of apamin. We have studied the structure of P401 in solution by high-resolution two-dimensional 1H-NMR spectroscopy. Almost all the backbone proton resonances have been assigned by sequential assignment strategy. Analysis of NOEs shows that P401 has a conformation very similar to that of apamin. N-terminal residues Ile-1-Cys-5 are in an extended conformation and residues His-13-Asn-22 on the C-terminus are in an alpha-helical structure. These two secondary structural elements are connected by two tight turns.
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PMID:Structure of P401 (mast cell degranulating peptide) in solution. 323 81


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