CATHEPSIN-D IS A GOOD CANDIDATE FOR THE SPECIFIC RELEASE OF A STABLE HEMORPHIN FROM HEMOGLOBIN IN-VIVO - W-HEMORPHIN-7

Hemorphin peptides, issued from hemoglobin, are emerging as endogenous bioactive peptides derived from in vivo tissular degradation of hemog lobin. In order to find the enzymes which could be implicated in the i n vivo release of these peptides, the major lysosomal enzyme cathepsin D was selected, and a study of its activity towards hemoglobin and he morphins was performed. In this paper, it is shown that according to t he primary specificity of cathepsin D towards hemoglobin, this enzyme could constitute a good candidate for the in vivo release of two hemor phins: LVV-hemorphin-7 and VV-hemorphin-7. Moreover, these products, e specially VV-hemorphin-7, are resistant to an extended cleavage by the enzyme. Although LVV-hemorphin-7 exhibits a lower resistance, an exte nded incubation with cathepsin D led to the release of the stable pept ide VV-hemorphin-7. (C) 1998 Academic Press.