Localization of the aspartic acid residue present in the active center of porcine pepsin

It is known that the catalytic center of porcine pepsin includes the 6-carboxy group of aspar t ic acid. The use of diazoacetyl inhibitors has enabled the amino-acid sequence containing the "active" aspar t ic acid to be shown [1, 2]: I l e V a l A s p T h r G l y T h r S e r . However, the part of the polypeptide chain of pepsin in which this sequence is present has not hitherto been known.