Abstract Enzymes capable of digesting collagen and non-collagenous proteins are present in implants of bone matrix. In the early stages of bone morphogenesis, implants produce relatively large amounts of trypsin-labile proteins and have high non-collagenolytic neutral proteinase and low collagenase activities. Enzymatic activity is maximal three weeks after implantation. The results indicate that increased synthesis of non-collagenous proteins and non-collagenolytic proteinases precedes the induction of significant amounts of collagenases. The importance of these findings in bone morphogenesis is discussed.