Human Heart and Platelet Actins Are Products of Different Genes

Abstract

The amino acid sequences of selected cyanogen bromide peptides from human blood platelet actin and human cardiac muscle actin were compared; it was found that, at position 129, platelet actin has threonine, and that cardiac muscle actin has valine. Thus human cytoplasmic and myofibrillar actins must be synthesized under the control of different genes.