The study was designed to determine the potential of collagen hydrolysate produced from the skin of Kacang goat through chymotrypsin hydrolysis to be used as an inhibitor of angiotensin converting enzyme (ACE). This research was conducted in three replications, with the measured parameters include ACE inhibitory potential and collagen hydrolysate fractionation. The results showed that collagen extraction of Kacang goat skin by chymotrypsin hydrolysis yielded 9.74% (dry matter, v/v) collagen, with pH at 6.6. The extracted collagen contained α1, α2, and β collagen chains with molecular weights of 151 kDa, 141 kDa, and 240 kDa, respectively. Furthermore, the collagen hydrolysis produced protein peptides confirmed at molecular weights of 43 to 107 kDa. The hydrolysate fractionation at molecular weights of <3 kDa, 3-5 kDa, and >5 kDa showed proteins concentrations of 2.33 mg/mL, 3.81 mg/mL, and 3.93 mg/mL, respectively. The hydrolysate fractionation with molecular weight <3 kDa showed to have ACE inhibition activity with the IC50 value of 0.47 mg/mL. The study concluded that collagen hydrolysate extracted from the skin of Kacang goat had a promising potential as a source of antihypertensive agent.

Background and Aim: Angiotensin-converting enzyme (ACE) is one of the inhibitory enzymes isolated from animals for the treatment of hypertension. ACE inhibitor (ACE-I) peptides can be obtained by hydrolyzing proteins from various animal tissues, including muscle and connective tissues. However, the study on ACE-I activity from collagen of Kacang goat skin has not been conducted. This study explores the potency of collagen from Kacang goat skin as a source of an antihypertensive agent through ACE inhibition. Thermolysin will hydrolyze collagen and produce the peptide classified antihypertensive bioactive peptides. This study aimed to determine the potential of thermolysin to hydrolyze collagen of Kacang goat skin for ACE-I peptide production and to identify the production of ACE-I peptides. Materials and Methods: Collagen from Kacang goat skin was hydrolyzed with thermolysin and incubated at 37°C for 1 h. Molecular weight (MW) evaluation was performed by SDS PAGE; fractionation peptides at <5 kDa, 3-5 kDa, and <3 kDa were performed by ultrafiltration and ACE-I activity determined by IC50 measurement. Results: Collagen was hydrolyzed by thermolysin, resulting in protein with MW of 117.50-14.60 kDa. The protein content of fractionation at >5 kDa was 3.93±0.72 mg/mL, content of 3-5 kDa was 3.81±0.68 mg/mL, and that of <3 kDa was 2.33±0.38 mg/mL. Fractionation was performed 3 times and one of the results was selected for the ACE-I test. The selected fraction was tested by IC50 measurement with three repetitions and it showed an average enzyme activity at 0.83 μg/mL or 82.94 mg/mL. Conclusion: Thermolysin hydrolysis of collagen from Kacang goat skin showed the potential to produce bioactive peptides, such as ACE-I.

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