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)

1. Incubation of NADH-ubiquinone oxidoreductase (Complex I) with chymotrypsin caused loss of rotenone-sensitive ubiquinone-1 reduction and an increase in rotenone-insensitive ubiquinone reduction. 2. Within the same time-course, NADH-K(3)Fe(CN)(6) oxidoreductase activity was unaffected. 3. Mixing of chymotrypsin-treated Complex I with Complex III did not give rise to NADH-cytochrome c oxidoreductase activity. 4. Gel electrophoresis in the presence of sodium dodecyl sulphate revealed selective degradation of several constituent polypeptides by chymotrypsin. 5. With higher chymotrypsin concentrations and longer incubation times, a decrease in NADH-K(3)Fe(CN)(6) oxidoreductase was observed. The kinetics of this decrease correlated with solubilization of the low-molecular-weight type-II NADH dehydrogenase (subunit mol.wts. 53000 and 27000) and with degradation of a polypeptide of mol.wt. 30000. 6. Phospholipid-depleted Complex I was more rapidly degraded by chymotrypsin. Specifically, a subunit of mol.wt. 75000, resistant to chymotrypsin in untreated Complex I, was degraded in phospholipid-depleted Complex I. In addition, the 30000-mol.wt. polypeptide was also more rapidly digested, correlating with an increased rate of transformation to type II NADH dehydrogenase.
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PMID:Effects of proteolytic digestion by chymotrypsin on the structure and catalytic properties of reduced nicotinamide-adenine dinucleotide-ubiquinone oxidoreductase from bovine heart mitochondria. 41 83

Scinderin, a novel Ca2+-activated actin filament-severing protein, has been purified to homogeneity from bovine adrenal medulla using a combination of several chromatographic procedures. The protein has an apparent mol. wt of 79,600 +/- 450 daltons, three isoforms (pIs 6.0, 6.1 and 6.2) and two Ca2+ binding sites (Kd 5.85 x 10(-7) M, Bmax 0.81 mol Ca2+/mol protein and Kd 2.85 x 10(-6) M, Bmax 1.87 mol Ca2+/mol protein). Scinderin interacts with F-actin in the presence of Ca2+ and produces a decrease in the viscosity of actin gels as a result of F-actin filament severing as demonstrated by electron microscopy. Scinderin is a structurally different protein from chromaffin cell gelsolin, another actin filament-severing protein described. Scinderin and gelsolin have different mol. wts, isoelectric points, amino acid composition and yield different peptide maps after limited proteolytic digestion by either Staphylococcus V8 protease or chymotrypsin. Moreover, scinderin antibodies do not cross-react with gelsolin and gelsolin antibodies fail to recognize scinderin. Immunofluorescence with anti-scinderin demonstrated that this protein is mainly localized in the subplasmalemma region of the chromaffin cell. Immunoblotting tests with the same antibodies indicated that scinderin is also expressed in brain and anterior as well as posterior pituitary. Presence of scinderin and gelsolin, two Ca2+-dependent actin filament-severing proteins in the same tissue, suggests the possibility of synergistic functions by the two proteins in the control of cellular actin filament networks. Alternatively, the actin filament-severing activity of the two proteins might be under the control of different transduction and modulating influences.
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PMID:Chromaffin cell scinderin, a novel calcium-dependent actin filament-severing protein. 215 78

1. Four cyclic AMP phosphodiesterase-activating activities, designated as A, B, C and D, were isolated from lugworm, Arenicola cristata, by preparative flat-bed isoelectric focusing. Activators C and D were further purified by TSK 3000SW HPLC to homogeneity. 2. Activators A, B, C, and D corresponded to pIs of 4.4, 5.0, 5.2 and 5.4; their mol wts were estimated to be 36,200, 30,500, 30,200 and 28,300 respectively. 3. The protease nature of these activities were confirmed by the inhibition by several trypsin inhibitors of their activation of phosphodiesterase and by their hydrolysis of TAME, a synthetic trypsin substrate. Only protease A also hydrolyzed BTEE, a chymotrypsin substrate.
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PMID:Isolation from lugworm (Arenicola cristata) of four proteases that activate cyclic AMP phosphodiesterase. 282 20

The chemical structure of carcinoembryonic antigen (CEA) and two closely related antigens, normal fecal antigen-2 (NFA-2) in normal adult feces and nonspecific cross-reacting antigen-2 (NCA-2) in the meconium, were further analyzed comparatively. The NH2-terminal amino acid sequence of NCA-2 was newly determined to position 18 and found to be identical to that so far determined for CEA- and NFA-2. After proteolytic digestion with chymotrypsin or protease V8, the digests of these antigens showed two groups of fragments upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. One consisted of the sharply banded fragments which were identical in all antigens and stained only with Coomassie brilliant blue (CBB) (five bands in the range 2500-10,000 daltons for chymotrypsin and 11 bands in the range 8000-35,000 daltons for protease V8, respectively), and the other consisted of the dispersed fragments which had variable mol. wts in the range 10,000-100,000 and were stainable with both CBB and periodic acid-Schiff reagent. Elution profiles of CEA, NFA-2, and NCA-2 from lectin columns, especially from concanavalin A-Sepharose columns, suggested some differences in oligosaccharide chains between them. These results indicate that the fundamental chemical structure of these antigens seems to be very similar to one another and is divided into two parts; an homologous portion(s) which is common to all three antigens and contains no sialylated sugar components, and a heterogeneous portion(s) which is variable among these antigens and contains sialylated sugar components.
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PMID:Further comparative studies on chemical properties of carcinoembryonic antigen in tumor tissues and closely related antigens in adult feces and meconium. 388 29

Treatment of human C4b-binding protein (C4BP) with cyanogen bromide gave five major peptides and limited proteolysis with chymotrypsin yielded two fragments. The yields, apparent mol. wts and N-terminal amino acid sequences of these peptides and fragments indicates that in dissociating conditions, after reduction of disulphide bonds, C4BP is composed of only one type of polypeptide chain of approx. 70,000 mol. wt. The amino acid sequence data obtained, which accounts for over 55% of the total sequence, allows an alignment of the cyanogen bromide peptides. In addition the amino acid sequence data indicates that the 70,000-dalton polypeptide chain of C4BP contains nine internal homology regions, each 60 amino acids long, which would account for 540 of the expected 600 amino acids in C4BP. Similar internal homology regions are found within the Ba region of factor B [Morley and Campbell, EMBO J. 3, 153-157 (1984)] and it is of interest that the regions found in C4BP are homologous to those found in Ba.
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PMID:Amino acid sequence studies of human C4b-binding protein: N-terminal sequence analysis and alignment of the fragments produced by limited proteolysis with chymotrypsin and the peptides produced by cyanogen bromide treatment. 403 66

Brief digestion of ox neurofilaments with trypsin liberates fragments that are soluble and have molecular weights ranging from 164 000 to 97 000. Peptide fingerprinting indicates that these regions, termed the tryptic head-regions, arise from the 205 000- and 158 000-mol.wt. components of the triplet. The remains of the parent polypeptides sediment with normal filaments and have been termed tail-regions. Digestion of neurofilaments with chymotrypsin also liberates soluble fragments (chymotryptic head-regions) but these have mol.wts. 171 000 and 119 000, though they too originate from the higher-molecular-weight triplet polypeptides. Tryptic and chymotryptic head-regions have extensive homology, and a low (less than or equal to 20%) helix content. Electron microscopy shows that chymotryptic digestion rapidly reduces the length of filaments, probably because this enzyme preferentially attacks the 72 000-mol.wt. polypeptide. In contrast, brief digestion with trypsin does not reduce filament length even though more than 90% of the two higher-molecular-weight components have been cleaved. These results indicate that the backbone of native filaments is formed from the 72 000-mol.wt. polypeptide together with the tail-regions from the 205 000- and 158 000-mol.wt. polypeptides. The corresponding head-regions of these components, which can represent nearly 75% of each molecule, are not necessary for preserving the backbone of native neurofilaments and are therefore good candidates for being the side arms that connect these filaments in nerve cells.
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PMID:The proteolytic digestion of ox neurofilaments with trypsin and alpha-chymotrypsin. 641 39

Branched-chain alpha-ketoacid dehydrogenase is a multienzyme complex composed of four subunits. The 46,500-dalton protein is a subunit of the decarboxylase component, which is selectively digested by chymotrypsin. Two peptides of apparent mol. wts. of 36,000 and 15,000 result with loss of enzyme activity. When the complex is saturated with thiamin pyrophosphate and ketoacid substrate, digestion by chymotrypsin does not occur. These data provide direct physical evidence for the stabilization of the complex by the presence of the vitamin B1-derived cofactor.
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PMID:Direct physical evidence for stabilization of branched-chain alpha-ketoacid dehydrogenase by thiamin pyrophosphate. 647 55