Enterokinase Substrate GDDDDK-betaNA

GDDDDK-βNA is a chromogenic/fluorogenic enteropeptidase substrate containing the canonical acidic Asp-Asp-Asp-Asp-Lys recognition motif followed by β-naphthylamide. Enteropeptidase cleaves after lysine in this sequence, releasing β-naphthylamine and enabling enzyme-activity measurements. The DDDDK motif mirrors the physiological specificity used by enteropeptidase to activate trypsinogen in the duodenum.

• enteropeptidase activity assays
• enterokinase specificity studies
• digestive serine-protease research
• enzyme inhibitor screening

This substrate reports enteropeptidase cleavage at the DDDDK motif but related proteases can contribute under nonselective conditions. Purified enzyme or appropriate inhibitor controls are recommended.

1. Bovine Proenteropeptidase Is Activated by Trypsin, and the Specificity of Enteropeptidase Depends on the Heavy Chain