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

A tissue carboxypeptidase-A-like enzyme was purified to apparent homogeneity from terminally differentiated epidermal cells of 2-day-old rats by potato inhibitor affinity chromatography followed by FPLC Mono Q column chromatography. The enzyme has an Mr of 35,000 as determined by SDS-polyacrylamide gel electrophoresis and HPLC gel filtration. It has a pH optimum of 8.5 for hydrolysis of benzyloxycarbonyl-Phe-Leu (Km = 0.22 mM, kcat = 57.9 s-1). The enzyme does not hydrolyze substrates with Arg, Lys and Pro at the C-terminal and Pro at the penultimate position. Angiotensin I was effectively hydrolyzed (Km = 0.06 mM, kcat = 6.48 s-1) and produced both des-Leu10-angiotensin I and angiotensin II. The enzyme activity, relatively stable at 4 degrees C and pH 8.0-10.5, was inactivated at pH values higher than 12.0 and lower than 5.0 or at 65 degrees C for 10 min. Inhibitor profiles of the epidermal enzyme also differed slightly from those of tissue carboxypeptidase A of pancreatic or mast cell origin.
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PMID:Purification and characterization of carboxypeptidase from terminally differentiated rat epidermal cells. 271 18

A glutamic acid residue at the active site of bovine lung angiotensin I-converting enzyme, a zinc-metallo peptidyl dipeptidase, was esterified with p-[N,N-bis(chloroethyl)amino]phenylbutyryl-L-[U-14C]proline (chlorambucyl-L-[U-14C]-L-proline), an affinity label for this enzyme (Harris, R.B., and Wilson, I.B. (1983) J. Biol. Chem. 258, 1357-1362). The radiolabeled enzyme was digested with BrCN and only 1 of the 30 cleavage peptides resolved by reverse-phase high performance liquid chromatography (HPLC) contained the bound radiolabel. This active-site peptide (Mr = 16,000) was digested with trypsin and the labeled peptide formed (T-2) was further degraded with thermolysin. The thermolytic peptides were resolved by reverse-phase HPLC. Only 1 of the 5 peptides obtained (Th-1, Mr = 1290) contained the bound radiolabel. Th-1 (12 residues) was subjected to manual Edman degradation and the following partial sequence was determined: H2N-Phe-Thr-Glu-Leu-Ala-Asp-Ser-Glu... The radiolabel was released at cycle 3 and the amount recovered was equivalent to the amount of phenylthiohydantoin-Glu detected on HPLC. Thus, glutamic acid is esterified with chlorambucyl-L-[U-14C]proline in confirmation of our earlier findings. The sequence determined is homologous in 5 residues with the corresponding sequences of bovine carboxypeptidase A and B, two other mammalian zinc proteases. There is little sequence homology with thermolysin, a bacterial zinc protease that also contains an essential active-site glutamic acid residue.
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PMID:Sequencing of an active-site peptide of angiotensin I-converting enzyme containing an essential glutamic acid residue. 285 12

The opioid peptide antagonist, ICI 174864 ([allyl]2-Tyr-alpha-amino-isobutyric acid (Aib)-Aib-Phe-Leu-OH), can produce analgesic effects in mice. The present study explored the possibility that ICI 174864 1) may have affinity and agonist efficacy at mu receptors and/or 2) may form a carboxypeptidase degradation product in vivo that possesses mu agonist activity. In vitro, ICI 174864 (10(-7) to 10(-4) M) inhibited the twitch in the electrically stimulated mouse vas deferens (ED50 = 90 microM) and guinea pig ileum (ED50 greater than 10(-4) M). The in vitro partial agonist activity of ICI 174864 was due to interaction with delta and not mu receptors because the apparent dissociation constant for naloxone using ICI 174864 as the agonist was similar to the apparent dissociation constant for the interaction of naloxone with delta and not mu receptors. Thus, ICI 174864 is a weak partial agonist at delta receptors with little affinity or efficacy at mu receptors. The incubation of ICI 174864 with carboxypeptidase A generated a peptide, LY281217 [(allyl)2-Tyr-Aib-Aib-Phe-OH], which was a more potent agonist in the mouse vas deferens and guinea pig ileum than ICI 174864. The agonist activity of LY281217 was due to interaction with mu and not delta receptors because LY281217 was approximately 100-fold more potent than ICI 174864 as an agonist in the guinea pig ileum, the apparent dissociation constant for naloxone using LY281217 as the agonist was similar to the apparent dissociation constant for the interaction of naloxone with mu receptors and the delta selective antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Opioid agonist activity of ICI 174864 and its carboxypeptidase degradation product, LY281217. 287 70

A glutamic acid residue at the active-site of bovine lung angiotensin I-converting enzyme was esterified with p-[N,N-bis-(chloroethyl)amino]phenylbutyryl-L-[U-14]-Proline (chlorambucyl-L-[U-14C]-L-Proline), an affinity label for this enzyme. The radiolabeled enzyme was digested with BrCN and only 1 of the 30 cleavage peptides resolved by reverse-phase HPLC contained the bound radiolabel. This active-site peptide (Mr approximately 16,000) was digested with trypsin, and the labeled peptide (T-2) was further degraded with thermolysin. The enzyme digest peptides were also resolved by reverse-phase HPLC. Only 1 of the 5 peptides obtained after thermolysin digestion (Th-1, Mr 1290) contained the bound radiolabel. Th-1 (12 residues) was subjected to manual Edman degradation and the following partial sequence was determined: H2N-Phe-Thr-Glu-Leu-Ala-Asp-Ser-Glu. The radiolabel was released at cycle 3 and the amount recovered was equivalent to the amount of PTH-Glu detected on HPLC. Thus, glutamic acid is esterified with chlorambucyl-L-[U-14C]-Proline which confirms our earlier findings. The sequence that we determined is homologous in five residues with the corresponding sequences of carboxypeptidase A and B, two other mammalian zinc-proteases. There is little sequence homology with thermolysin, a bacterial zinc-protease that also contains an essential active-site glutamic acid residue.
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PMID:Isolation and sequencing of an active-site peptide from angiotensin I-converting enzyme. 302 71

In preliminary studies of antigen-induced airway inflammation, we noted an apparent increase in peribronchiolar mast cell number. Experiments were thus undertaken to investigate the nature of this migration of mast cells into the central and peripheral airway epithelium and to determine its time course. The tracheae and small airways of 10 anesthetized mongrel dogs were exposed via a bronchoscope to Ascaris suum antigen (Ag), fMet-Leu-Phe (fMLP), ovalbumin (OVA), and isotonic saline (SAL). In the central airways, all stimuli provoked a significant increase (P less than 0.05) in mast cell numbers at the base of the airway epithelium within 3 h. In the peripheral airways, only Ag aerosol stimulated a significant mast cell increase compared with unexposed tissue. In a second series of experiments, the trachea of seven dogs were exposed to 0.026, 0.26, and 2.6 micrograms of Ag. The tissue was collected at 1, 3, 6, and 10 h after exposure. In these experiments, there was a significant mast cell increase seen within 1 h but it was not dose dependent. By 6-10 h after exposure, mast cell counts were not significantly different from the unexposed condition, which is consistent with the idea that some of the cells either degranulated or migrated into the airway lumen. We conclude that mast cell migration is an acute response that can be demonstrated within 1 h of stimulation with Ag. The observation that nonimmunological stimuli may, in some cases, also stimulate mast cell movement affords the possibility that this process represents a generalized response to airway irritation.
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PMID:Rapid increase in mast cell numbers in canine central and peripheral airways. 340 88

Carboxypeptidase A and B were partially purified from the soluble fraction of longitudinal muscle layer (myenteric plexus) of bovine small intestine. The obtained carboxypeptidase A hydrolyzed [Met]enkephalin-Arg6-Phe7 and [Leu]enkephalin, but [Met]enkephalin was not a suitable substrate for the enzyme. The Km value of carboxypeptidase A for [Met]enkephalin-Arg6-Phe7 was 0.74 mM and that for [Leu]enkephalin was 0.44 mM. Intestinal carboxypeptidase B hydrolyzed [Met]enkephalin-Arg6, liberating [Met]enkephalin, and the Km value of the enzyme for [Met]enkephalin-Arg6 was 0347 mM.
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PMID:Separation of carboxypeptidase A and B from longitudinal muscle layer of bovine small intestine: their properties regarding hydrolysis of enkephalins and enkephalin-analogs. 345 45

The secretory granules of rat serosal mast cells are able efficiently to degrade the apolipoprotein B component of low density lipoproteins (LDL) Kokkonen, J. O., and Kovanen, P. T. (1985) J. Biol. Chem. 260, 14756-14763). The granules are known to contain two neutral proteases with complementary specificities: a chymotrypsin-like endopeptidase called chymase, and an exopeptidase, the granule carboxypeptidase A. The role of this enzyme pair in the proteolytic degradation of LDL was studied with the aid of specific enzyme inhibitors. Incubation of LDL with intact granules (both enzymes active) led to the formation of numerous low molecular weight peptides and the liberation of free amino acids, most of which (95%) were aromatic (Phe, Tyr, Trp) or branched-chain aliphatic (Leu, Ile, Val). Selective inhibition of granule carboxypeptidase A (leaving chymase active) blocked the liberation of free amino acids, but left the formation of peptides uninhibited. On the other hand, selective inhibition of granule chymase (leaving carboxypeptidase A active) totally abolished the proteolytic degradation of LDL. The results are consistent with a model according to which the proteolytic degradation of LDL by mast cell granules results from coordinated action of the two granule-bound enzymes, whereby the chymase first cleaves peptides from the apolipoprotein B of LDL, and thereafter the carboxypeptidase A cleaves amino acids from the peptides formed.
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PMID:Low density lipoprotein degradation by secretory granules of rat mast cells. Sequential degradation of apolipoprotein B by granule chymase and carboxypeptidase A. 353 21

The substrate specificity of rat mast cell protease I (RMCP I), a chymotrypsin-like serine protease localized in the secretory granules of mast cells, was compared to that of bovine alpha-chymotrypsin by using several peptide and protein substrates of known amino acid sequences. Although the overall specificities of the two proteases appeared similar, subtle but significant differences were observed. RMCP I was more prone than chymotrypsin to hydrolyze peptide bonds consisting of Leu-Xaa or two hydrophobic residues--e.g., Phe-Phe. Additionally, the hydrolysis of angiotensin I catalyzed by chymotrypsin, but not by RMCP I, resulted in the generation of angiotensin II as an intermediate product. In contrast to the solubilized enzyme, the RMCP I activity within the insoluble granules was completely stable for at least 2 months in suitable buffers at pH 8.0 or pH 7.2, at 4 degrees C. Carboxypeptidase A activity associated with isolated mast cell granules was completely inhibited by 10 mM o-phenanthroline. Polypeptides smaller than apomyoglobin (17,199 Da) were rapidly hydrolyzed by granule-bound RMCP I, whereas apomyoglobin and other larger proteins were not hydrolyzed. In contrast, the free protease readily hydrolyzed the larger proteins. Neither normal rat serum nor alpha 1-antitrypsin, both of which inhibited the activity of free RMCP I, was effective in inhibiting granule-associated RMCP I. The results indicate that granule-bound RMCP I is not released into solution from isolated secretory granules under physiological conditions of ionic strength and pH and that the granule structure limits the size of proteins that can be hydrolyzed by the protease.
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PMID:Substrate specificity of the chymotrypsin-like protease in secretory granules isolated from rat mast cells. 354 Sep 62

Synovial biopsy specimens from 20 patients with rheumatoid arthritis were subjected to quantitative analysis for several parameters of inflammation and for enumeration of synovial tissue mast cells. Strong positive correlations were found between numbers of mast cells per cubic millimeter of synovial tissue and the following synovial tissue parameters: inflammatory index (a quantification of lymphocytic infiltration), Leu-3a grade (T helper/inducer lymphocytes), Leu-1 grade (T lymphocyte), and plasma cell grade. A strong negative correlation was found between the synovial mast cell count and the extent of sublining layer fibrin deposition. Correlations between synovial mast cell count and Leu-2a grade, ratio of Leu-3a grade:Leu-2a grade, OKM1 grade, HLA-DR grade, and lining layer thickness grade did not reach statistical significance. In addition, we obtained synovial specimens from 6 of the patients both before and after long-term therapy with oral methotrexate and from 3 of the patients before, and 1 week after, an intraarticular injection of steroid. The 3 patients who had an intraarticular steroid injection showed a 67-96% decrease in the number of synovial tissue mast cells; there was no significant change in the number of synovial mast cells in the tissues of the 6 patients who received oral methotrexate. These observations are the first documentation of a quantitative relationship between the number of mast cells and the number and phenotypic profile of infiltrating lymphocytes in an inflamed tissue, which in this case, is human synovium. Our findings suggest that mast cells are involved in the pathologic interactions in rheumatoid arthritis and might play a role in the early phases of exacerbations of disease activity.
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PMID:Mast cell numbers in rheumatoid synovial tissues. Correlations with quantitative measures of lymphocytic infiltration and modulation by antiinflammatory therapy. 354 31

Thionoleucine S-anilide (Leut-anilide), Leut-Gly-OEt and Leut-Phe-OMe were synthesized and shown to be competitive inhibitors of leucine aminopeptidase from pig kidney. The kinetics of inhibition were determined in the presence of leucine 4-methylcoumarin-7-amide as substrate. Although the compounds showed only moderate inhibitory potency, it was found that all were resistant to hydrolysis by the enzyme, in contrast with the reported behaviour of some thionopeptide analogues of substrates for other Zn2+-peptidases such as carboxypeptidase A and angiotensin-converting enzyme.
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PMID:The behaviour of leucine aminopeptidase towards thionopeptides. 366 53


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