Effects of Basic Nuclear Proteins on Cardiac Muscle Function
A method for the preparation of semipurified basic proteins from cardiac muscle was presented. At low ionic strengths (below 0.05) and in the presence of Mg++, these compounds, as well as purified histones from a variety of tissues, inhibited the Mg++-ATPase activity of cardiac and skeletal muscle actomyosin or myofibrillar suspensions. Under similar conditions, a retardation of superprecipitation occurred. At high ionic strengths (above 0.06) the histones stimulated the Mg++-ATPase.
In the presence of Ca++, and at all ionic strengths studied, the histones elicited a marked stimulation of actomyosin ATPase.
Administration of histones to anesthetized, open-chest guinea pigs, caused a significant depression of the force of contraction of the hearts. These data suggest a possible involvement of basic nuclear proteins in cardiac activity.
- Accepted June 15, 1965.
- © 1965 American Heart Association, Inc.