Inhibition of α-amylase by sea cucumber intestinal collagen hydrolysates

Starch digestion regulation is important for blood glucose control and weight management. α-Amylase inhibitors are one of major interventions for blood glucose reduction and weight management. Sea cucumber intestines are marine by-products with extensive bioactive compounds like collagen, however, research on their α-amylase inhibitory mechanisms remains limited. In this study, sea cucumber intestinal collagen hydrolysates (SCICHs) were generated by enzymatic hydrolysis (pepsin, neutral protease, and trypsin), and their interaction with α-amylase were investigated through spectroscopic and kinetic analysis. SCICHs were found to interact with α-amylase and assemble enzyme-hydrolysate complexes. Such interactions exhibited concentration-dependent behavior, progressively diminishing the catalytic activity of α-amylase while simultaneously eliciting conformational rearrangements in its secondary structure. The tryptic hydrolysate showed the highest inhibitory activity, achieving 64.71% inhibition rate comparable to the positive control (acarbose). Enzymatic kinetic analysis indicated that SCICHs suppress α-amylase activity via a reversible mixed-type inhibitory mode, which can bind to both the unbound enzyme and the enzyme-substrate complex, displaying a higher affinity toward the free enzyme. These findings imply that SCICHs possess the capacity to suppress α-amylase and hold potential as a natural constituent for formulating functional foods targeting obesity control.