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)

A technique utilizing Pregnant Mare's Serum Gonadotropin and Human Chorionic Gonadotropin treatment of hens (Gallus domesticus), followed by manual ovulation of the excised follicles, was developed to obtain a large number of mature ova. The intact ova were used to test whether acrosin, partially purified from the spermatozoa of the cock (Gallus domesticus), partially purified rabbit testicular acrosin and commercial preparations of several hydrolytic enzymes could dissolve the inner vitelline membrane. Enzymes were applied to pieces of filter paper placed on the ovum. Cock acrosin and endopeptidases such as trypsin, chymotrypsin, collagenase and elastase hydrolyzed the membrane whereas exopeptidases such as leucine aminopeptidase and carboxypeptidase A did not. Phospholipase A, sulfatase, hyaluronidase, beta-glucuronidase and rabbit testicular acrosin also failed to hydrolyze the membrane. Cock acrosin hydrolysis of the ovum surface was inhibited by soybean trypsin inhibitor. The surface of the ovum over the germinal disc region was hydrolyzed more quickly by cock acrosin than the surface over other regions of the ovum. Acrosin from cock sperm caused the release of trichloroacetic acid soluble material absorbing at 280 nm from sonicated preparations of inner vitelline membranes. Hydrolysis was greatest at pH 8.0 and was inhibited by soybean trypsin inhibitor.
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PMID:Hydrolysis of the hen egg vitelline membrane by cock sperm acrosin and other enzymes. 0 Apr 54

Urinary metabolites of ring 14C-labeled 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea (Methyl CCNU) from rats have been isolated and characterized by high-performance liquid chromatography and mass spectrometry. About 44% of the cyclohexyl moiety of CCNU was excreted in 24 hr and included approximately 10% of the excreted dose as free amines and 40% as conjugates that could be converted to amines by hydrolysis. Amine composition of free base plus hydrolyzable conjugates was 55% hydroxycyclohexylamines (3-trans, 3-cis, 4-cis, and 4-trans) and 30% cyclohexylamine. This strongly supports previous studies which indicated that CCNU is largely hydroxylated in vivo as well as in vitro. Rats pretreated with phenobarbital excreted high relative amounts of cis-4-hydroxy derivatives (41%), again showing a high degree of correlation between in vitro and in vivo results. Treatment of urine with beta-glucuronidase gave no apparent increase in free amines. However, sulfatase was about 25% as effective as alkaline hydrolysis for releasing free amines from whole urine. Major urinary metabolites were found to have m.w. of about 629, 413, 329, and 243 and represented 55%, 20%, 20%, and 5% of total excreted 14C, respectively. It was concluded that the higher m.w. metabolites may be conjugates of peptides possibly derived from active site-directed inactivation of specific enzymes. Previous work has shown that enzymes such as chymotrypsin and glutathione reductase are inhibited by isocyanates in this manner. Hydroxylated metabolites of Methyl CCNU had a pattern similar to that of CCNU. The major free (12%) and conjugated amine (54%) metabolites of Methyl CCNU in the urine in decreasing order of quantity present were cis-3-hydroxy-trans-4-methylcyclohexylamine, trans-4-methylcyclohexylamine, trans-4-hydroxymethylcyclohexylamine, and trans-3-hydroxy-trans-4-methyl-cyclohexylamine.
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PMID:Urinary metabolites of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea. 611 12

Often used to remove sulfate groups from carbohydrates, the regulatory properties of the aryl sulfatase from Helix pomatia remain little characterized. As many hydrolytic enzymes utilize exogenous metal ions in catalysis, the effect of various divalent metal ions on the sulfatase was investigated. Evidence for metal ion activation was collected, with Cd(2+) being notable for effective activation. The enzyme was inhibited by Cu(2+). The response of other common hydrolases to divalent metal ions was characterized. Activation by Cd(2+) was not observed for chymotrypsin, rabbit liver esterase, or beta-galactosidase. Instead, Cd was found to inhibit both the esterase and the galactosidase. Inhibition by Cu(2+) and Zn(2+) was also observed for some of these hydrolases.
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PMID:Evidence for the Cd(2+) activation of the aryl sulfatase from helix pomatia. 1633 54