Cystatin M/E is a high affinity inhibitor of the asparaginyl endopeptidase legumain, and we
have previously reported that both proteins are likely to be involved in the regulation of
stratum corneum formation in skin. Although cystatin M/E contains a predicted binding site
for papain-like cysteine proteases, no high affinity binding for any member of this family has
been demonstrated so far. We report that human cathepsin V (CTSV) and human cathepsin
L (CTSL) are strongly inhibited by human cystatin M/E. Kinetic studies show that K i values of …