ABSTRACT
The glandular kallikreins of the mouse submandibular gland have been the most highly studied of any kallikrein system. The corresponding gene locus is a large multigene family consisting of 24 closely related genes or pseudogenes. The growth factor precursors are thus substrates for specific glandular kallikreins, while the mature processed forms of these same growth factors are effective inhibitors of the same kallikreins. The nerve growth factor high molecular weight complex is structurally and evolutionarily related to the larger protease precursors and complexes important in the regulation of bloodclotting. Serine protease zymogen activation requires the cleavage of an N-terminal propeptide, which contains seven amino acid residues in glandular kallikreins, followed by folding of the new N-terminus characterized by a highly conserved Ile-Val-Gly-Gly sequence into the interior of the protein. The precursor form of Epidermal Growth Factor is a large and potentially multifunctional molecule.
