Kinetics Study of Protein Hydrolysis and Inhibition of Angiotensin Converting Enzyme by Peptides Hydrolysate Extracted from Walnut
Raheleh Jahanbani, Mahmood Ghaffari, Kourosh Vahdati, Maryam Salami, Mohammadreza Khalesi, Nader Sheibani, Ali Akbar Moosavi-Movahedi
International Journal of Peptide Research and Therapeutics
Bioactive peptides are defined as protein-based components having nutritional value and have proved roles important for the human health. In this study inhibition of angiotensin converting enzyme (ACE) by protein-based hydrolysate extracted from walnut (Juglanse regia. L.) seeds was evaluated. The peptide fraction obtained by enzymatic hydrolysis with trypsin showed higher ACE-inhibitory and lower IC50 value (0.39 ± 0.05 mg/mL) than obtained by hydrolysis with chymotrypsin and proteinase K. The study of kinetics showed that by increasing the concentration of the trypsin hydrolysate from 0.01–0.5 mg/mL, Km increased, while Vmaxdecreased. Also the value of Ki was found to be 0.17 ± 0.01 mg/mL, which means that binding affinity for the substrate decreased in the presence of inhibitor. The structural studies of ACE demonstrated that, in comparison with a commercial antihypertension drug (enalapril), the trypsin hydrolysate had no effect on secondary structure and less tertiary structure changes of protein was observed.
Circular dichroism, Secondary structure, Chemical stability, Biochemistry