Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Outer dynein arm polypeptides that possess Mg+2-adenosine triphosphatase (ATPase) activity have been extracted from the flagellar axonemes of demembranated bovine sperm. Electron microscopy of intact and salt-extracted sperm demonstrates a relatively selective removal of the outer dynein arms. The salt extract contains a specific ATPase activity of 55 nmoles inorganic phosphate (Pi)/min/mg protein. Sucrose density gradient centrifugation of this extract results in a 6-fold increase in specific activity of ATPase (333 nmole/Pi/min/mg protein), which sediments as a single 13S peak. Concomitant with the increase in specific activity, there is enrichment of three high molecular weight polypeptides (Mr greater than 300,000) characteristic of dynein heavy chains. ATPase activities in the initial extract and in the 13S peak are inhibited by concentrations of vanadate and erythro-9-[3-2-(hydroxynonyl)]adenine similar to those that inhibit ATPase activity in sea urchin sperm dynein. These findings indicate that outer arm dynein ATPase can be extracted and partially purified from bovine sperm.
 ...
PMID:Partial purification and characterization of dynein adenosine triphosphatase from bovine sperm. 296 Mar 84

bis-cyclopentadienyl [Cp] complexes of vanadium(IV) or vanadocenes are rapid and potent inhibitors of human sperm motility with potential as a new class of contraceptive agents. We investigated the utility of boar sperm as a model system to study the mechanisms of drug action because boar sperm lacks phosphocreatine and creatine kinase activity, the essential components of the "phosphagen shuttle" system for human sperm motility. Two representative vanadocenes, vanadocene dichloride [VDC] and bis[pentamethylcyclopentadienyl] vanadium dichloride [VPMDC], in which the bis-Cp rings were substituted with five electron-donating methyl groups were evaluated. The concentration-dependent effects of VDC and VPMDC on spermicidal activity, axonemal dynein adenosine triphosphatase (ATPase) activity, and tyrosine phosphorylation of global sperm proteins were assessed by computer-assisted sperm analysis, spectrophotometry, and immunoblotting, respectively. Both the unsubstituted and the pentamethyl-substituted vanadocene induced rapid sperm immobilization (T(1/2) < 15 s). Substitution of the bis-Cp rings by five methyl groups augmented the SIA of VDC threefold. The EC(50) values for VDC and VPMDC were 2.1 and 0.76 microM, respectively. Spermicidal activity of vanadocenes was not associated with the inhibition of dynein ATPase(s) or increase in tyrosine phosphorylation of sperm proteins. These results suggest that the potent spermicidal activity of vanadocenes against boar sperm is mediated by a unique mechanism that is independent of dynein ATPase activity, phosphatase activity, and phosphocreatine/creatine kinase system. Therefore, boar sperm is a suitable model for further investigating the molecular mechanism of spermicidal action of vanadocenes.
 ...
PMID:Evaluation of boar sperm as a model system to study the mechanism of spermicidal activity of vanadocenes. 1077 10