Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a preliminary study of the enzyme-polymer interactions, the role of 15 enzymes in the in vitro hydrolysis of polyglycolic acid has been investigated. Carboxypeptidase A, alpha-chymotrypsin, clostridiopeptidase A and ficin increase the rate of hydrolysis of this synthetic polymer, illustrating the ability of enzymes to influence polymer degradation.
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PMID:Enzyme-accelerated hydrolysis of polyglycolic acid. 21 Jan 60

We have investigated the transmembrane topology of the bovine heart mitochondrial porin by means of proteases and antibodies raised against the amino-terminal region of the protein. The antisera against the human N-terminus reacted with porin in Western blots of NaDodSO4-solubilized bovine heart mitochondria and with the membrane-bound porin in enzyme-linked immunosorbent assay (ELISA). The immunoreaction with mitochondria coated on microtiter wells showed that the amino-terminal region of the protein is not embedded in the lipid bilayer but is exposed to the cytosol. Back-titration of unreacted anti-N-terminal antibodies after their incubation with intact mitochondria demonstrated that the porin N-terminus is also exposed in "noncoated" mitochondria. No difference in antisera reactivity was observed between intact and broken mitochondria. Intact and broken mitochondria were subjected to proteolysis by specific proteases. The membrane-bound bovine heart porin was strongly resistant to proteolysis, but a few specific cleavage sites were observed. Staphylococcus aureus V8 protease gave a large 24K N-terminal peptide, trypsin produced a 12K N-terminal and an 18K C-terminal peptide, and chymotrypsin gave two peptides of Mr 19.5K and 12.5K, which were both recognized by the antiserum against the human N-terminus. Carboxypeptidase A was ineffective in cleaving the membrane-bound porin in both intact and broken mitochondria. Thus, the carboxy-terminal part of the protein is probably not exposed to the water phase. The cleavage patterns of membrane-bound porin, obtained with S. aureus V8 protease, trypsin, and chymotrypsin, showed no difference between intact and broken mitochondria, thus indicating that all porin molecules have the same orientation in the membrane. The computer analysis of the sequence of human B-lymphocyte porin suggested that 16 beta-strands can span the phospholipid bilayer. This result, together with the overall information presented, allowed us to draw a possible scheme of the transmembrane arrangement of mammalian mitochondrial porin.
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PMID:Peptide-specific antibodies and proteases as probes of the transmembrane topology of the bovine heart mitochondrial porin. 171 14

Porcine pancreatic hydrolases in juice and homogenate surveyed by electrophoretic separation in agarose gel, at pH 8.6 and subsequently characterized using substrates of various specificity, either directly in the gel or after transfer to nitrocellulose (enzymoblotting) showed: Anodal and cathodal trypsin with Bz-Arg-pNA. Chymotrypsin A, B, and C with similar, but not identical, activities to Suc-Ala-Ala-Pro-Phe-pNA, Bz-Tyr-pNA, Suc-Phe-pNA and Ac-Phe-beta NE and with differences in their molecular weights and electrophoretical charges. Elastase I and protease E with Suc-(Ala)3-pNA and MeO-Suc-Ala-Ala-Pro-Val-pNA and elastase I also with elastin. Elastase II with the chymotrypsin substrates and with elastin. Carboxypeptidase A with CN-Phe. Amylase with blue starch polymer.
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PMID:Identification and characterization of eight porcine pancreatic proteinases, carboxypeptidase A and amylase after electrophoretic separation using specific substrates. 244 43

The effect of the proteolysis of aldolase on both the substrate specificity of the enzyme and binding capacity for actin have been studied. Carboxypeptidase A, trypsin, chymotrypsin and pepsin, all acted to cleave peptides from the C-terminal portion of the enzyme, resulting initially in a marked loss of activity towards fructose-1:6-bisphosphate (FBP), without impairment of activity towards fructose-1-phosphate (F1P). In some cases, however, further proteolysis caused reductions in activity with F1P as well. By correlating the size of the peptide fragments released by these enzymes with the known sequence of aldolase, evidence has been provided that cleavage of His-359 and/or Tyr-361 lead to the loss of FBP activity, while further cleavage of up to six amino acids begin to affect activity against F1P, as well. In regard to the ability of the proteolysed aldolase to bind to F-actin, it was evident from these studies that binding ability was not impaired in the initial stages of proteolysis referred to above, but was retained until the enzyme was extensively degraded. This differential behaviour of the active and binding sites on aldolase clearly establish their separate topographical localization. These results have been discussed in relation to the positioning of these separate sites on the enzyme, the nature of the interaction between aldolase and actin and the phenomenon of enzyme ambiquity in cells and tissues.
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PMID:Evidence for the spatial separation of the binding sites for substrate and for cytoskeletal proteins on the enzyme aldolase. 308 Mar 48

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

Proteases stimulate mouse erythroleukemia (MEL) cell differentiation and multiplication. The stimulation of differentiation is synergistically increased by low concentrations of dimethyl sulfoxide. Synergism of other low molecular weight inducers with representative proteases, alpha-chymotrypsin and protease V8, was tested. Hemin. hypoxanthine, actinomycin D, aminonucleoside of puromycin, hexamethylene bisacetamide, and 5-azacytidine were also found to act synergistically with this protease to augment MEL cell hemoglobin production, but not cell multiplication. Fatty acids (acetate, propionate, butyrate, isobutyrate, and valerate), prostaglandins A1 and E1, amino acids, and amino acid analogs and metabolites did not act synergistically with chymotrypsin. Some physiologic amino acids were found to be weak inducers. Several of the low molecular weight inducers also acted synergistically with protease V8 in inducing differentiation, and, as with chymotrypsin, did not act synergistically in stimulating cell multiplication. Like chymotrypsin, protease V8 did not act synergistically with butyrate. The earlier finding that proteases, but not low molecular weight inducers, stimulate cell multiplication during the induction of differentiation was confirmed. Carboxypeptidase A also was found to be an inducer.
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PMID:Proteases act synergistically with low molecular weight inducers to stimulate mouse erythroleukemia cell differentiation. 635 99

The primary structure of human D, the serine protease activating the C3 convertase of the alternative complement pathway, has been deduced by sequencing peptides derived from various chemical (CNBr and o-iodosobenzoic acid) and enzymatic (trypsin, lysine protease, Staphylococcus aureus V8 protease, and chymotrypsin) cleavages. Carboxypeptidase A was also used to confirm the COOH-terminal sequence. The peptides were purified by high-pressure liquid chromatography. The proposed sequence of human D contains 222 amino acids and has a calculated molecular weight of 23 748. It exhibits a high degree of homology with other serine proteases, especially around the NH2-terminus as well as the three residues corresponding to the active-site His-57, Asp-102, and Ser-195 (chymotrypsinogen numbering). This sequence homology is highest (40%) with plasmin, intermediate (35%) with pancreatic serine proteases, such as elastase, trypsin, chymotrypsin, and kallikrein, and least (30%) with the serum enzymes thrombin and factor X. D, however, exhibits only minimal amino acid homology with the other sequenced complement serine proteases, Clr (25%) and Bb (20%). The substitution of a basic lysine for a neutral amino acid three residues NH2-terminal to the active-site serine as well as a small serine residue for a bulky aromatic amino acid at position 215 (chymotrypsinogen numbering) in the binding pocket may be important in determining the exquisite substrate specificity of D. The presence of His-40 which interacts with Asp-194 (chymotrypsinogen numbering) to stabilize other serine protease zymogens [Freer, S. T., Kraut, J., Robertus, J. D., Wright, H. T., & Xuong, N. H. (1970) Biochemistry 9, 1997] argues in favor of such a D precursor molecule.
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PMID:Amino acid sequence of human D of the alternative complement pathway. 638 66

The inside-out configuration of the patch-clamp method was used to study the effects of trypsin on the activity of ATP-sensitive potassium (K-ATP) channels from isolated mouse pancreatic beta-cells. Trypsin (20 micrograms/ml) irreversibly enhanced channel activity around twofold by reducing the interburst intervals without altering the burst kinetics. No effect on the single channel conductance or the inward rectification produced by internal Mg2+ was observed: however, the protease did reduce the inhibitory effect of Mg2+ on channel activity. Trypsin both prevented rundown of K-ATP channel activity and reactivated the channels after complete rundown. These effects of trypsin were absent in the presence of trypsin inhibitor. The protease also reduced the inhibitory effect of ATP on channel activity, increasing the dissociation constant from 7 to 49 microM. Trypsin removed the activating effect of ADP (0.1 mmol/l) on channel activity and reduced the inhibitory effect of tolbutamide (0.5 mmol/l). Carboxypeptidase A did not activate K-ATP channels in excised patches, although it was able to slightly reactivate channels after complete rundown, whereas chymotrypsin increased K-ATP channel activity but it did not produce reactivation. The effects of papain were similar to those of trypsin.
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PMID:Modification of K-ATP channels in pancreatic beta-cells by trypsin. 835 Dec 6

Crotamine, a basic, myonecrotic, histamine-releasing neurotoxin, was isolated from Crotalus durissus terrificus venom. Carboxypeptidase A was shown to be activated by crotamine when acting upon N-carbobenzoxyglycil-L-phenylalanine. However the activity of carboxypeptidase B upon the substrate hippuryl-L-arginine was not enhanced by this toxin. Teh basic histamine releasers protamine and compound 48/80 also activated carboxypeptidase A. These three agents activated both alpha-chymotrypsin when acting upon acetyl-L-tyrosine ethyl ester and also five snake venom phospholipase-like myotoxins acting upon egg yolk phosphatidylcholine. These findings suggest that the action of these agents during histamine release may involve the participation of specific intermediary hydrolases which, upon activation, would enhance their cytolytic effects on the sequence of events which lead to granule extrusion and histamine release from mast cells.
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PMID:The histamine releasers crotamine, protamine and compound 48/80 activate specific proteases and phospholipases A2. 930 35

Cultivation of functional pancreatic cells isolated from adult mammalian pancreas remains difficult. We developed a differentiation protocol that gradually induced the formation of mouse pancreatic exocrine cells from embryonic stem cells (ESCs). This process mimicked in vivo pancreatic development by directing cells through definitive endoderm (DE), gut tube endoderm, and pancreatic progenitor cells to differentiated cells that expressed pancreatic exocrine enzymes. Mouse ESCs were cultured in hanging drops to form embryoid bodies. Treatment of embryoid bodies with activin A induced the formation of DE cells that expressed marker mRNAs Goosecoid and Mixl1 and that were double-positive with Foxa2 and Sox17 proteins. Subsequent treatment of the DE cells by retinoic acid induced the formation of gut tube endoderm cells that expressed the specific marker Hnf1b. Expression of Goosecoid and Mixl1 was downregulated during this period. Fibroblast growth factor 7 (FGF7) promoted differentiation of PDX1-expressing pancreatic progenitor cells that also expressed Foxa2 mRNA, an endodermal marker, suggesting derivation from the DE cells. Exocrine cell differentiation was induced with FGF7, glucagon-like peptide-1, and nicotinamide. The differentiated cells expressed mature pancreatic exocrine cell mRNAs, such as Amylase, Elastase, and Carboxypeptidase A. Additionally, they produced pancreatic elastase, amylase, carboxypeptidase A, and chymotrypsin proteins that were identified in cytoplasmic granules by immunocytochemistry. Active amylase was released into the medium. Moreover, FGF7 was associated with differentiation of pancreatic exocrine cells. The findings reported here offer a novel and effective process to develop pancreatic exocrine cells from ESCs.
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PMID:A novel stepwise differentiation of functional pancreatic exocrine cells from embryonic stem cells. 2088 97


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