The alpha-subunit of mouse 7 S nerve growth factor is an inactive serine protease.

Tryptic and cyanogen bromide peptides accounting for approximately 85% of the amino acid sequence of the alpha-subunit of mouse 7 S nerve growth factor have been isolated and extensively sequenced. The partial structure revealed a high degree of identity with the gamma-subunit (greater than 80%), which is an arginine esteropeptidase of the serine protease family. However, the alpha-subunit does not cleave synthetic arginine ester or peptide substrates nor is it labeled by diisopropylfluorophosphate. The lack of catalytic activity may result from a Gly----His substitution near the active site serine or from the blocked NH2 terminus.