Purification and characterization of angiotensin converting enzyme-inhibitory derived from crocodile blood hydrolysates

Abstract Various enzyme types were used to hydrolyze crocodile blood peptides showing an Angiotensin I-converting enzyme (ACE) inhibitory activity. Alcalase hydrolysates (ALH) and Protease G6 hydrolysates (PG6H) showed the highest degree of hydrolysis (P<0.05). However, PG6H was significantly observed to have an effective ACE-inhibitory (ACE-I) activity (94.23%) with an IC50 of 0.021±0.02 mg/mL. An unbound fraction of PG6H showed the highest ACE-I activity and was then subjected to two steps RP-HPLC process. The potent fractions including RC1 and RC2 exhibiting the highest ACE-I activity (88.33 & 84.54%, respectively) were identified using LC-MS/MS. Two novel ACE-inhibitory peptides were identified as GVAAN (431.25 Da) and LHALLL (679.52 Da), and characterized by GRAVY were 60 and 83%, respectively. The crocodile blood hydrolysate obtained by Protease G6 could serve as a source of ACE-inhibitory activity for physiological benefits.