Angiotensin and bradykinin metabolism by peptidases identified in skeletal muscle.

We have identified angiotensin-converting enzyme, neutral endopeptidase-24.11, and aminopeptidase M in a purified glycoprotein fraction of rabbit skeletal muscle membranes. The identification was based on substrate specificity and sensitivity to selective inhibitors. Angiotensin I metabolism was due to angiotensin-converting enzyme-mediated conversion to angiotensin II and neutral endopeptidase-24.11-mediated conversion to angiotensin(1-7). Bradykinin was degraded by angiotensin-converting enzyme and neutral endopeptidase-24.11; angiotensin II by neutral endopeptidase-24.11; and angiotensin III by neutral endopeptidase-24.11 and aminopeptidase M. Thus, the effects of angiotensins and kinins on skeletal muscle blood flow and metabolism may be regulated by local angiotensin-converting enzyme, neutral endopeptidase-24.11, and aminopeptidase M.