title: An ecto-cyclic AMP-independent protein kinase in goat spermatozoa and its change of activity during forward motility.
abstract: Goat cauda-epididymal intact spermatozoa have been shown to possess an ecto-cyclic AMP-independent protein kinase activity on the external surface that causes phosphorylation of the serine and threonine residues of exogenous phosvitin. The enzyme is neither a tyrosine kinase nor a catalytic subunit of the cyclic AMP-dependent protein kinase. It is not activated by Ca2+, calmodulin and phosphatidylserine. The intact-cell enzyme is capable of phosphorylating a variety of proteins including sperm plasma membrane-bound phosphoprotein(s). The enzymic activity of the intact spermatozoa was not due to contamination of broken or "leaky" cells. The kinase activity of the whole cells was strongly inhibited by the non-penetrating surface probes: p-chloromercuriphenylsulphonic acid (10 microM) and proteases (125 micrograms/ml). The specific activity of the ecto-kinase increased nearly 100% during vigorous forward progression of spermatozoa.
mesh_terms: D000818:Animals; D004822:Epididymis; D006041:Goats; D007700:Kinetics; D008297:Male; D011494:Protein Kinases / Q000378:metabolism*; D013081:Sperm Motility; D013094:Spermatozoa / Q000201:enzymology / Q000502:physiology*; D013379:Substrate Specificity
chemical_list: D011494:Protein Kinases