Title : The complete amino acid
sequence of rat submaxillary gland
tonin does contain the
aspartic acid at the active
site : confirmation by protein sequence analysis
Abstract :
- The revised amino acid sequence of rat submaxillary gland tonin , a serine protease , does contain the active site Asp residue
- The active site of this kallikrein-related enzyme is thus made up of the same catalytic triad ( Asp, Ser, and His ) found in all known serine proteases. serine proteases
- The important Asp residue has now been localized in a 16 amino acid peptide previously reported as missing in the tonin sequence
- The complete amino acid sequence thus contains 235 residues corresponding to a molecular weight of 25,658, more in agreement with previously reported molecular weights
- Moreover, the revised structure led (a) to the assignment of Arg, Asn, and Val residues instead of His, Asp, and Gly at positions 63, 165, and 169 , respectively; (b) to the assignment of residues occupying an overlapping sequence at positions 165-171, and finally (c) to the localization of two N-glycosylation sites at positions 82 and 165
- These results further document the close relationship of tonin to the ever expanding kallikrein family