PEPTIDA BIOAKTIF -ANTIHIPERTENSI

Bioactive peptides are specific protein fragments that have a positive impact on functional and body conditions, have low molecular weight (1-300 Da), and generally consist of 2-20 amino acids (Kitts and Weiler, 2003).

Amino acids are organic compounds that have carboxyl (-COOH) and amine (-NH2) functional groups. Food derived from livestock products (milk, eggs and meat) has high protein content, so it is very appropriate as a source of bioactive peptides composed of various types of peptides that are strung through peptide bonds. Peptides can be separated from proteins by breaking peptide bonds from proteins so that a shorter structure is produced. However, peptides in food if consumed directly do not show the ability as an inhibitor. Lindawati (2019) lack of this ability because in the digestive tract, proteins that are biodegradable will be used by the digestive tract microbes so that the remaining amount is not yet capable as an inhibitor (Lindawati, 2019). The functional properties of bioactive peptides are determined by their amino acid makeup. The amino acid sequence Val-Pro-Pro or Ile-Pro-Pro has the function as an antihypertensive agent through inhibition of Angiotensin Converting Enzime (ACE).

Inhibition (ACE) is an inhibition of the activity of the ACE enzyme that causes hypertension by blocking the change in angiotensin I to angiotensin II which is a powerful vasoconstrictor causing hypertension (Liu et al., 2010., Korhonen and Pihlanto 2006).

                Bioactive peptides can be produced by 1) hydrolysis with digestive tract enzymes. The enzymes used to break peptide bonds from food proteins (milk), such as the enzymes trypsin, pepsin and chymotrypsin. 2) the fermentation method uses lactic acid bacteria. For example, fresh milk coupled with proteolytic lactic acid bacteria is able to biodegrade milk protein into peptides in a certain amino acid sequence. Different types of proteolytic microbes will produce different peptides that have different functions. An example in this article is the bioactive peptide from kefir.

Kefir is a fermented milk drink with kefir seeds for 24 hours incubation, containing short chain bioactive peptides (<1Da) that can inhibit hypertension through inhibition of ACE. Prediction of Glu-Cys-Asn amino acid composition; Pro-Ile; Pro-Pro-Ile: Pro-Gln-Gly; Leu-Ile-Pro-Pro (Lindawati 2018)

The mechanism of kefir bioactive peptides in inhibiting the activity of ACE, is a competitive inhibiting mechanism. ACE inhibiting peptides compiled by hydropobic amino acids interact with the active side of the ACE enzyme in the anpenultime and ultimate penultime, causing molecular structure changes on the active side of ACE so that angiotensin II is not formed (Wilson 2011). Published in the book "Kefir Fermented Milk as Anti-Hypertension" ISBN978-602-5742-92-7