title: Characterization of the ATP-phosphohydrolase activity of bovine spermatozoa flagellar extracts.
abstract: The ATP-phosphohydrolase activity of extracts prepared from bovine spermatozoa flagella (BSFE), was characterized with respect to enzyme, substrate, activator ion and salt concentration, temperature dependence and time stability. BSFE required the presence of a divalent cation for activity: Mg++ or Ca++ could function as activator; Mn++, Zn++ and Cd++ could not. EDTA, but not EGTA, was inhibitory to enzymatic activity. Ca++ inhibited the Mg++ stimulated activity. ATP was dephosphorylated more rapidly than GTP greater than CTP greater than ITP, and ADP was dephosphorylated at 40% of the rate of ATP. The magnesium activated ATPase was stimulated by potassium and inhibited by sodium ions. Activation of BSFE ATP-phosphohydrolase was maximal in the presence of Mg++ and ATP in equimolar concentrations and K+ (0.05-0.3 M) at 30 degrees C. Although the enzymatic activity of the extract was found to decrease rapidly with time, it could be maintained for up to three days by the addition of 2-beta-mercaptoethanol to the bovine spermatozoa flagellar extracts.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D002458:Cell Fractionation; D002474:Cell-Free System; D004355:Drug Stability; D004492:Edetic Acid / Q000494:pharmacology; D004789:Enzyme Activation; D005407:Flagella / Q000201:enzymology*; D005615:Freezing; D005990:Glycerol; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008623:Mercaptoethanol; D010758:Phosphorus / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D013094:Spermatozoa / Q000201:enzymology / Q000648:ultrastructure*; D013696:Temperature; D014020:Tissue Extracts
chemical_list: D014020:Tissue Extracts; D010758:Phosphorus; D008623:Mercaptoethanol; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D004492:Edetic Acid; D000251:Adenosine Triphosphatases; D008274:Magnesium; D005990:Glycerol; D002118:Calcium