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)

Partially purified calf brain uridine kinase precipitated by bivalent metal cations has been compared with the soluble enzyme fraction regarding its stability in the presence of inactivating factors. The freeze-dried preparations of uridine kinase precipitaated by Pb2+ or Zn2+ ions, althouth enzymatically highly active, are insoluble in aqueous solutions. The activity of metal-insolubilized enzymes disappears during their preincubation in acidic media or in the presence of silver ions. Also trypsin, chymotrypsin and cathepsin B1 caused decreases in enzyme activity. However, fractions which have been precipitated by metal ions and freeze-dried are stable at high temperatures, whereas the activity of soluble uridine kinase is completely lost. Both unheated metal-ion precipitated uridine kinase preparations and those heated at 100 degrees C are equally sensitive to the feedback inhibition by CTP.
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PMID:Stability of the insoluble form of uridine kinase coupled to zn2+ or pb2+ ions. 0 66

A phospholipase C which hydrolyzes [14C]phosphatidylcholine has been purified 1782-fold from 70% ammonium sulfate extract of bull seminal plasma. Purification steps included acid precipitation, chromatography on DEAE-Sephacel, concanavalin A, octyl-Sepharose 4B and Ultrogel AcA 34. The final step provided homogeneous phospholipase C as determined by polyacrylamide gel electrophoresis. The enzyme comprised two subunits, Mr 69,000 and Mr 55,000, respectively. The enzyme had an optimum at pH 7.2 and pI 5.0. EDTA, Cd2+, Pb2+, Ni2+, Fe2+, and Zn2+ inhibited phospholipase C activity. Km and Vmax on p-nitrophenyl phosphorylcholine and phosphatidylcholine substrates were 20 mM and 17 mumol/min/mg of the purified enzyme and 100 microM and 18 mumol/min/mg of the purified enzyme, respectively. The enzyme appeared to be localized in the acrosome as judged by the binding of anti-phospholipase C to the acrosome. This phospholipase C, unlike other known phospholipases (C), did not hydrolyze [1-14C]phosphatidylinositol. The testicular extract of the guinea pig contained inactive phospholipase C which was activated on incubation with acrosin and trypsin but not chymotrypsin.
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PMID:Isolation and properties of a phosphatidylcholine-specific phospholipase C from bull seminal plasma. 308 12

Lead was measured in the gastric and duodenal juice of three patients with lead poisoning (blood concentrations of lead: 4.30; 5.16; 5.50 mumol/l). The lead excretion into the gastric juice was 94.6; 29.9 and 18.3 nmol Pb X h-1 for the poisoned persons and 57.9 +/- 38.1 nmol Pb X h-1 for healthy persons (n = 20). Pentagastrin (6 microgram/kg, i.m.) stimulated lead excretion in both groups (normal + 109%, lead poisoned persons: + 180%; + 187%; + 311%). The lead excretion was correlated with an increase of HCl-secretion and volume in healthy persons. The lead excretion into the duodenal juice after secretion (1 unit/kg) amounted to 14.2 +/- 8.8 nmol Ph X h-1 in healthy persons, whereas after secretion plus caerulein 18.8 +/- 7.2 nmol Pb X h-1 were found. In the duodenal juice of the lead poisoned persons 27.5 and 474.9 nmol Ph X h-1 respec. were found after secretion and 58.9 and 491.8 nmol Pb X h-1 respec. after secretion plus caerulein. Lead excretion was correlated with enzyme secretion (trypsin and chymotrypsin).
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PMID:[Excretion of lead in the gastric and duodenal juice of persons with occupational lead poisoning and normal subjects]. 722 65