A modified pro-.alpha. chain comprising a triple helix forming domain
linked to at least an N-terminal domain, the N-terminal domain containing
a polypeptide from at least part of a laminin glycoprotein or secretory
leukocyte protease inhibitor. The pro-.alpha. chain may form part of a
procollagen molecule that has the N-terminal domain retained. The
procollagen molecule may be incorporated into collagen polymers, matrices
and gels and be used for such applications as wound healing.