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

Eight different di- and tripeptidyl aldehyde derivatives, each having at its C-terminus an aldehyde analog of L-norleucine, L-methionine, or L-phenylalanine with a preceding L-leucine residue, were synthesized and tested for their inhibitory effects on several serine and cysteine endopeptidases. These compounds showed almost no inhibition of trypsin, and only weak inhibition of alpha-chymotrypsin and cathepsin H, while they exhibited marked inhibition of cathepsin B less than calpain II congruent to calpain I less than cathepsin L, being stronger in this order. The mode of inhibition of these cysteine proteinases was competitive for the peptide substrate used and inhibitor constants (Ki) were calculated from the Dixon plot. The best inhibitors found were: 4-phenyl-butyryl-Leu-Met-H for calpain I (Ki, 36 nM) and calpain II (Ki, 50 nM); acetyl-Leu-Leu-nLeu-H for cathepsin L (Ki, 0.5 nM); acetyl-Leu-Leu-Met-H for cathepsin B (Ki, 100 nM).
 ...
PMID:Inhibitory effect of di- and tripeptidyl aldehydes on calpains and cathepsins. 207 36

We investigated the limited proteolysis of fast and slow myosins purified from rabbit psoas major and semimembranosus proprius muscles, respectively, by the main lysosomal proteinases: cathepsins B, H, L, and D. In EDTA containing buffer, cathepsin D cleaved both myosins only at the rod-S1 junction leading to the formation of two S1 fragments of slightly higher Mr than the three forms obtained with chymotrypsin. On addition of MgCl2 instead of EDTA, myosin hydrolysis was markedly reduced. In contrast, irrespective of the presence of either MgCl2 or EDTA, cathepsin B hydrolysed both myosins into HMM and LMM. Cathepsin L digested myosins more extensively than cathepsins B and D and the main fragments generated were, in decreasing order of importance, rod, S1, S2, HMM, and LMM. In the incubation conditions tested, cathepsin H displayed nondetectable action on myosins. As fast and slow myosin digest patterns were compared, the main differences observed concerned the size of the proteolytic products and the rate of hydrolysis, which was about 4-fold higher for the fast than for the slow isoform. This appeared consistent whatever enzyme was considered.
 ...
PMID:Lysosomal proteinase-sensitive regions in fast and slow skeletal muscle myosins. 254 27

Hydrolysis of histones by proteinases from rat liver, skin and other sources was studied by using a rat thymus histone preparation as the substrate and polyacrylamide-gel electrophoresis and densitometric analysis as the methods to detect histone subtypes and their hydrolysis. The rat mast-cell proteinase I effectively hydrolysed histones except type H4. Thrombin hydrolysed effectively histones H1 and H2A, whereas plasmin hydrolysed all types of histones. Cathepsin D hydrolysed especially histone H2A. Cathepsins B and L hydrolysed all histones more slowly, and cathepsin H hydrolysed them extremely slowly. Epidermal aminoendopeptidase did not hydrolyse histones. Trypsin and chymotrypsin were used as reference enzymes, which hydrolysed all types of histones in very low concentrations. This study suggests that a variety of proteinases could play a role in histone hydrolysis. Hydrolysis of a specific subtype of histones, such as histone H2A at pH 6 by cathepsin D, may be directly involved in regulation of epidermal-cell differentiation.
 ...
PMID:Hydrolysis of histones by proteinases. 296 88

The papain inhibitor from human spleen was purified by extraction in isotonic sucrose, acetone fractionation, papain-Sepharose affinity chromatography and gel filtration on Sephadex G-50. The purified inhibitor was fractionated by electrofocusing into four major isoelectric variants with pI values of 4.7, 5.0, 6.0 and 6.5. These variants can be classified into two groups: the acidic type, comprising the variants with pI 4.7 and 5.0, and the neutral type, comprising the variants with pI 6.0 and 6.5. The following properties distinguish the two types: 1. Immunological properties: antibodies raised against either of the neutral variants precipitated both of these, but not the acidic variants. The antiserum against the human epidermal cysteineproteinase inhibitor precipitated the acidic variants, but not the neutral variants. 2. Molecular size: two-dimensional electrophoresis of the purified inhibitor gave molecular weights of 11400 for the acidic variants and 12000 for the neutral variants. The pI 6.0 variant contained two compounds with molecular weights of 12000 and 12800. 3. Enzyme spectrum: human cathepsin B was inhibited by the acidic type, while the neutral type was a poor inhibitor. Both types inhibited cathepsin H, papain, ficin and bromelain, although the inhibition of bromelain did not exceed 70%. Human cathepsin D, bovine trypsin and chymotrypsin and porcine elastase were not inhibited by either type.
 ...
PMID:Human spleen cysteineproteinase inhibitor. Purification, fractionation into isoelectric variants and some properties of the variants. 618 75

A new papain inhibitor was purified from psoriatic epidermal scales using gel chromatography and anion exchange chromatography. The purified protein inhibited papain and ficin but not cathepsin B, cathepsin H, trypsin, or chymotrypsin. Isoelectric focusing revealed 3 major inhibitor variants with pI's of 7.3, 6.9, and 6.5. A Mr of 38,000 was obtained by a gel chromatographic method for the crude inhibitor. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis the Mr values of the isoelectric variants were: 43,000 for the variant pI 7.3, 43,000 and 35,000 for the variant pI 6.9, and 34,000-35,000 for the variant pI 6.5. An antiserum of the inhibitor was used to locate the inhibitor in the psoriatic and normal epidermis. In psoriatic epidermis, the inhibitor was found in the peripheral cytoplasm of spinous cells and in the scale. In normal epidermis, the staining was seen only in orifices of hair follicles. An inhibitor with similar size and antigenic properties to that isolated from the psoriatic scales was demonstrated in extracts made from the whole-thickness epidermis but not in extracts from the healthy epidermal scales, the dermis, the liver, the spleen, or the blood serum.
 ...
PMID:Partial purification and some properties of a new papain inhibitor from psoriatic scales. 639 31

Thiol protease inhibitors were found in the cytosol fractions of various rat tissues. An inhibitor, named cytosol thiol protease inhibitor, was purified from rat liver cytosol by acid treatment and column chromatographies on Sephadex G-50, DEAE-Sephadex and Sephadex G-75. The purified inhibitor gave a single protein band on sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The molecular weight of the inhibitor was found to be 12 400 by gel filtration on Sephadex G-75 and SDS-polyacrylamide gel electrophoresis, and its isoelectric point was found to be 5.04. This inhibitor inhibited rat liver lysosomal cathepsin B, B2, C, H and L and papain, but not cathepsin A or D, trypsin or chymotrypsin. The inhibitor caused noncompetitive inhibition of the hydrolytic activity of cathepsin H on alpha-N-benzoyl-DL-arginine 2-naphthylamide and its Ki value was 4.08 . 10(-8) M. Heat treatment at 80 degrees C for 10 min reduced the activity 40%.
 ...
PMID:Purification and properties of thiol protease inhibitor from rat liver cytosol. 702 26

The Western corn rootworm is one of the most economically important pests in corn. One possibility for controlling this pest is the cultivation of transgenic corn expressing Bacillus thuringiensis (Bt) toxins, such as Cry3A, Cry34Ab1/Cry35Ab1, and Cry3Bb1. However, widespread cultivation of the resulting Bt corn may result in the development of resistant pest populations. The Bt toxins are processed by proteases in the midgut of susceptible insects. Thus, protease activity studies were conducted using the midgut juice (pH 5.75) from third instars larvae of the susceptible Western corn rootworm. As a result, the activities of the serine endopeptidases trypsin, chymotrypsin, elastase, cathepsin G, plasmin, and thrombin; the cysteine endopeptidases cathepsin L, papain, cathepsin B, and cathepsin H; the aspartic endopeptidase pepsin; the metallo endopeptidase saccharolysin; the exopeptidase aminopeptidase, and the omegapeptidase acylaminoacylpeptidase were detected. These results are of basic interest but also lead to reference systems for the identification of protease-mediated resistance mechanisms in potentially resistant individuals.
 ...
PMID:Protease activities in the midgut of Western corn rootworm (Diabrotica virgifera virgifera LeConte). 1932 44