Inhibitor of α-Glucosidase (AGH, EC 3.2.1.20). Tyr-Tyr-Pro-Leu which showed a potent inhibition against yeast AGH was selected as a skeleton peptide. As summarized five peptides were synthesized , and the AGH inhibition was determined. In comparison with the inhibitory activity of original tetra-peptide (IC50 = 3.7 mM), Pro-Leu and Tyr-Pro as well as Val-Trp (IC50 = 22.6 ± 0.36 mM) showed no or less inhibition strongly suggests that tri-peptide chain length is required to decrease the action of AGH. Since Tyr-Pro showed poor inhibition, Leu at the C-terminus was found to be most important for binding to or interact with the active site of AGH.
Table 1 AGH inhibitory activity of synthetic analogues of the peptide isolated from muscle hydrolyzate a
Sequence
| IC50 (mM)
| | Tyr-Tyr-Pro-Leu | 3.7 ± 0.02 | | Tyr-Pro-Leu | 3.9 ± 0.02 | Pro-Leu
| No inhibition
| Tyr-Pro
| 16.8 ± 0.08
| Tyr-Pro-Gly
| 5.0 ± 0.01
| Tyr-Pro-Tyr
| 25.8 ± 0.12
| a The analogue peptides were synthesized on the basis of the sequence of Tyr-Tyr-Pro-Leu isolated from the hydrolyzate.
|