the mutant precursors studied included two with amino acid substitutions in the 32-amino-acid leader peptide ( glycine for arginine at position 23 , designated gly23 ; glycines for arginines at positions 15 , 23 , and 26 , designated gly15,23,26 ) and two with deletions ( deletion of residues 8 to 22 , designated d8-22 ; deletion of residues 17 to 32 , designated n16 ) .
C0002520
amino-acid
C0017890
glycines