The investigation of antibacterial properties of peptides and protein hydrolysates derived from serum of Asian water monitor (Varanus salvator).

It is well known that the Asian water monitors or Varanus salvator are both scavengers and predators. They can live and survive in the place that exposed to harmful microorganisms. Most people believe that they have some protected mechanisms to confront those infections. The aim of this study is to determine the antibacterial activities of crude peptides and protein hydrolysates extracted from serum of the Varanus salvator. Ten types of bacteria were cultured with crude peptides and protein hydrolysates which were isolated from 21 Varanus salvator's serum. The crude peptides showed some interested inhibition percentages against Enterobacter aerogenes ATCC13048 = 25.6%, Acinetobacter baumannii ATCC19606 = 33.4%, Burkholderia cepacia ATCC25416 = 35.3% and Pseudomonas aeruginosa ATCC27853 = 25.8%, whereas the protein hydrolysates had some inhibition potential on Burkholderia cepacia ATCC25416 = 24.3%. For the rest results of other tests were below 20% of inhibition. In addition, the evidences show that crude peptides have better antibacterial performances significantly than protein hydrolysates on most tested bacteria. Furthermore, antimicrobial peptides prediction shows about 10 percent hit (41/432 sequences). The interpretation shows that the best hit sequence is highly hydrophobic. It may destroy outer membrane of Gram-negative hence prevents the invasion of those bacteria. Altogether, bioinformatics and experiments show similar trends of antimicrobial peptide efficacy from Varanus salvator. Further studies need to be conducted on peptide purification and antimicrobial peptide candidate should be identified.