Presence in human skeletal muscle of an AMP deaminase-associated protein that reacts with an antibody to human plasma histidine-proline-rich glycoprotein

Histidine-proline-rich glycoprotein (HPRG) is a protein that is synthesized by parenchimal liver cells. The protein has been implicated in a number of plasma-specific processes, including blood coagulation and fibrinolysis. W e have recently reported the association of an HPRG-like protein with rabbi t skeletal muscle AMP deaminase (AMPD). The results of the immunological an alysis reported here demonstrate that an antibody against human plasma HPRG reacts with an AMPD preparation from human skeletal muscle. To probe the l ocalization of the putative HPRG-like protein in human skeletal muscle, ser ial sections from frozen biopsy specimens were processed for immunohistoche mical and histoenzymatic stains. A selective binding of the anti-HPRG antib ody to Type IIB muscle fibers was detected, suggesting a preferential assoc iation of the novel protein to the AMPD isoenzyme contained in the fast-twi tch glycolytic fibers.