Analisis Aktivitas Inhibitor Angiotensin-Converting Enzyme (ACE) Peptida Bioaktif Susu Kambing Peranakan Etawa

Abstract

Peptida bioaktif merupakan hasil pemecahan protein yang bermanfaat untuk kesehatan dengan bekerja sebagai antioksidan, antidiabetes, dan antihipertensi. Salah satu mekanisme dari sifat antihipertensi peptida bioaktif adalah inhibisi angiotensin-converting enzyme (ACE). Penghambatan ACE dengan inhibitor alami menjadi alternatif untuk menghindari efek samping obat sintetik. Penelitian ini bertujuan untuk mengetahui pengaruh proses hidrolisis terhadap kadar protein, inhibisi ACE, dan profil protein susu kambing peranakan Etawa. Dalam penelitian ini, susu kambing yang telah dipisahkan lemaknya dihidrolisis enzim papain dengan aktivitas spesifik 1,48 ± 0,04 U/mg pada suhu 55 oC selama 1, 4, dan 24 jam. Analisis kadar protein dilakukan dengan metode Bradford, aktivitas inhibitor ACE dengan ACE Kit-WST, dan profil protein dengan SDS-PAGE. Susu kambing yang dihidrolisis mengalami penurunan kadar protein dan peningkatan inhibisi ACE yang signifikan. Waktu hidrolisis yang lebih lama juga meningkatkan inhibisi ACE. Pada larutan susu kambing konsentrasi 7,5 mg/mL, hidrolisat 24 jam menunjukkan aktivitas tertinggi sebesar 95,01 ± 1,13% dibandingkan nonhidrolisis sebesar 84,49 ± 0,93%. Obat kaptopril sebagai kontrol positif menunjukkan aktivitas sebesar 101,25 ± 0,56% pada konsentrasi ≥ 0,1 µg/mL. Hasil elektroforesis susu kambing menunjukkan enam pita protein dengan berat molekul 11-84 kDa. Setelah proses hidrolisis, hidrolisat protein hanya menunjukkan dua pita protein 11 dan 16 kDa, menunjukkan bahwa hidrolisis memotong protein berukuran besar menjadi peptida dengan berat molekul lebih kecil. Penelitian ini berpotensi pada pengembangan pangan fungsional yang dapat mencegah dan mengobati hipertensi. Kata kunci: antihipertensi, inhibitor ACE, peptida bioaktif, susu kambing

Bioactive peptides are the result of protein breakdown which are beneficial for health by working as antioxidant, antidiabetic, and antihypertensive. One mechanism of the antihypertensive properties from bioactive peptides is the inhibition of angiotensin-converting enzyme (ACE). Inhibiting ACE with natural inhibitors is an alternative to avoid the side effects of synthetic drugs. This study aims to determine the effect of hydrolysis on protein content, ACE inhibition, and the protein profile of Etawah crossbreed goat milk. In this study, goat milk that has had its fat separated was hydrolyzed by papain enzyme with specific activity of 1.48 ± 0.04 U/mg at 55 oC for 1, 4 and 24 hours. Analysis of protein content was carried out using the Bradford method, ACE inhibitor activity with ACE Kit-WST, and protein profile with SDS-PAGE. Hydrolyzed goat milk had a significant decrease in protein content and increase in ACE inhibition. Longer hydrolysis time also increases ACE inhibition. In the goat milk solution with a concentration of 7.5 mg/mL, 24-hour hydrolysate showed the highest activity at 95.01 ± 1.13% compared to non-hydrolysis at 84.49 ± 0.93%. The captopril as positive control showed activity at 101.25 ± 0.56% at a concentration of ≥ 0.1 µg/mL. The result of goat milk electrophoresis showed six protein bands with a molecular weight of 11-84 kDa. After hydrolysis, the protein hydrolysates only showed two protein bands of 11 and 16 kDa, indicating that hydrolysis cleaves large protein into peptides with smaller molecular weight. This research has the potential to develop functional foods that can prevent and treat hypertension. Keywords: ACE inhibitor, antihypertensive, bioactive peptide, goat milk