title: On the interaction of bovine seminal RNase with actin in vitro.
abstract: Ribonuclease from bovine seminal plasma (RNase BS) interacts with skeletal muscle actin in the following way: it binds to actin with an apparent binding constant of 9.2 X 10(4) M-1 in 0.1 M KCl, induces the polymerization of actin below the critical concentration in depolymerization buffer, accelerates the salt-induced polymerization of actin even at a molar ratio of RNase to actin lower than 1/100, and bundles F-actin filaments. In the bundles the molar ratio of RNase to actin is about 0.66. Actin inhibits the enzymatic activity of RNase BS. RNase A from bovine pancreas, which is structurally almost identical to the subunits of RNase BS as well as a monomeric form of RNase BS, do not cross-link actin filaments and have a much smaller effect on the polymerization of actin. We conclude that the dimeric structure of the RNase BS, which consists of two identical subunits cross-linked by interchain disulfide bridges, is probably responsible for the bundling activity and the accelerating effect on the polymerization of actin.
authors.forename: F C
authors.initials: FC
authors.lastname: Simm
authors.forename: W K
authors.initials: WK
authors.lastname: Krietsch
authors.forename: G
authors.initials: G
authors.lastname: Isenberg
mesh_terms: D000199:Actins / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001704:Biopolymers; D002021:Buffers; D002417:Cattle; D066298:In Vitro Techniques; D008297:Male; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D011485:Protein Binding; D011817:Rabbits; D012260:Ribonucleases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012661:Semen / Q000201:enzymology*
chemical_list: D000199:Actins; D001704:Biopolymers; D002021:Buffers; D012260:Ribonucleases