PURIFICATION AND PROPERTIES OF CALDESMON-LIKE PROTEIN FROM MOLLUSCAN SMOOTH-MUSCLE

In this comparative study, the heat-stable protein content of scallop muscles was reinvestigated, The hCaD-like protein was prepared and its properties carefully examined. The heat-stable high-molecular-mass ca ldesmon-like (hCaD-like) protein is only present in the catch (smooth) muscle and it is completely absent in the striated muscle of scallop. The isolated scallop hCaD-like protein cosediments with F-actin, bind s to myosin significantly and inhibits the ATPase activity of acto-myo sin. A partial cDNA clone from a Mytilus anterior byssus retractor mus cle (ABRM)-related protein showed strong homology with the hCaD gizzar d sequence. This allowed identification of the heat-stable 100-110 kDa protein doublet band isolated in this study as a caldesmon-like molec ule.