The molecular basis for diminished muscle function in acidosis: a proposal

Abstract

A testable molecular proposal for the effects of acidosis on skeletal and cardiac muscle is presented. It is based on fluorescence studies published in 1974, which provided evidence for carboxylates in an EF-hand Ca²⁺ binding site having an abnormal pKa. This results in an H⁺-bound Blocked substate in the 3-state model of muscle regulation whose contribution inhibits myosin binding in the pH 7 to 6 range. A schematic cartoon illustrates the substate within the 3-state model.

Keywords: 3-states; Acidosis; Calcium; Muscle regulation; Protons; Troponin.