Role of glandular kallikreins as growth factor processing enzymes: structural and evolutionary considerations.

Hormones and growth factors are generally released from larger precursors by limited proteolysis. The causative agents remain poorly defined with respect to location and properties. One subset of proteases, the glandular kallikreins, have been implicated in a few cases, in part because of their specific association with mature forms of some hormones. However, limited distribution and low copy number in some species cast doubt on this hypothesis, and they may well play other physiological functions that remain to be elucidated.