Showing papers on "GTP-Binding Protein alpha Subunits published in 1987"
TL;DR: The structure of these pertussis toxin substrates is similar, but not the same in invertebrate, lower vertebrate, or mammalian spermatozoa, and partial peptide maps of porcine spermatozosan M, 41,000 protein and the a subunit of Porcine brain Gi(G,i) are identical.
Abstract: Guanine nucleotide-binding proteins or G proteins have been shown to couple cell-surface receptors to second messenger effector systems such as adenylate cyclase or phosphodiesterase in a variety of cells. G,(N,), Gi(Ni), G,(N,), and transducin, are composed of three subunits, a, j3, and y , and the a subunits are specifically ADP-ribosylated by the bacterial enzymes cholera toxin or pertussis toxin. Resolved by Na.dodecyl.S04 (SDS)-polyacrylamide gel electrophoresis, the (Y subunits have apparent molecular weights (M, ) of 39,000 to 52,000. Kopf and colleagues' and our laboratory2 have shown the presence of pertussis toxin substrates in spermatozoan membranes of M , 39,000 to M , 41 ,000. Here, we show that the structure of these pertussis toxin substrates is similar, but not the same in invertebrate, lower vertebrate, or mammalian spermatozoa. In addition, partial peptide maps of porcine spermatozoan M , 41,000 protein and the a subunit of porcine brain Gi(G,i) are identical. It was shown previously that the chymotryptic map of sea urchin M , 39,000 protein was identical to brain Ciao2.