This peptide is an enterokinase substrate. Enterokinase, also known as enteropeptidase, is a membrane-bound serine endopeptidase that initiates the activation of pancreatic hydrolases by cleaving and activation of trypsinogen. Enteropeptidase is present in the duodenum. Proendopeptidase may be also detected after activation with trypsin and cleavage of this substrate.