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The interaction of bovine sperm particles and human platelet membranes was studied with regard to adenylate cyclase activity. When sperm and platelet membrane preparations were combined, greater than additive adenylate cyclase activity was measured. Data obtained after inactivation of the sperm enzyme indicated that the observed increase in adenylate cyclase activity was not due to an activation of the sperm cyclase but that a sperm component, which could be extracted from the sperm particles, activated the platelet adenylate cyclase. Platelet cyclase activation by the sperm particles was a saturable and time-dependent process. The extent of activation was particularly high (up to 10-fold) in the presence of a stable GTP analog. Under this condition, the apparent affinity of the platelet enzyme for Mg2+ was increased by about one order of magnitude, whereas with Mn2+ only a minor effect of the sperm particles was observed. Platelet adenylate cyclase stimulation by prostaglandin E1 (up to 20-fold) was more than doubled by the sperm particles, whereas the inhibition of the platelet enzyme by epinephrine was abolished. The sperm factor was trypsin-sensitive and was inactivated by boiling. The data indicate that bovine sperm particles contain an extractable protein, which activates platelet adenylate cyclase probably by inactivating an inhibitory site.
K H Jakobs, and
R A Johnson, and
G Schultz
February 1983,
Thrombosis research,
K H Jakobs, and
R A Johnson, and
G Schultz
January 1984,
Journal of andrology,
K H Jakobs, and
R A Johnson, and
G Schultz
November 1978,
Biology of reproduction,
K H Jakobs, and
R A Johnson, and
G Schultz
July 1980,
Journal of reproduction and fertility,
K H Jakobs, and
R A Johnson, and
G Schultz
September 1974,
Thrombosis research,
K H Jakobs, and
R A Johnson, and
G Schultz
March 1977,
Prostaglandins,
K H Jakobs, and
R A Johnson, and
G Schultz
October 1979,
Biochemical Society transactions,
K H Jakobs, and
R A Johnson, and
G Schultz
January 1974,
Endocrine research communications,
K H Jakobs, and
R A Johnson, and
G Schultz
January 1984,
Annals of the New York Academy of Sciences,
K H Jakobs, and
R A Johnson, and
G Schultz
February 1986,
Archives of biochemistry and biophysics,
