Identification and molecular docking study of novel cholesterol esterase inhibitory peptides from camel milk proteins

Abstract

Novel bioactive peptides from camel milk protein hydrolysates (CMPH) were identified and tested for inhibition of cholesterol esterase (CEase), and their possible binding mechanisms were elucidated by molecular docking. Papain-generated CMPH showed the highest degree of hydrolysis. All CMPH produced upon enzymatic degradation demonstrated a dramatic enhancement of CEase inhibition compared with intact camel milk proteins, with papain-generated hydrolysate P 9 displaying the highest inhibition. Peptide identification and their modeling through PepSite 2 revealed that among 20 potential bioactive peptides in alcalase-generated hydrolysate A 9 , only 3 peptides, with sequences KFQWGY, SQDWSFY, and YWYPPQ, showed the highest binding toward CEase catalytic sites. Among 43 peptides in 9-h papain-generated hydrolysate P 9 , 4 peptides were found to be potent CEase inhibitors. Molecular docking revealed that WPMLQPKVM, CLSPLQMR, MYQQWKFL, and CLSPLQFR from P 9 hydrolysates were able to bind to the active site of CEase with good docking scores and molecular mechanics-generalized born surface area binding energies. Overall, this is the first study reporting CEase inhibitory potential of peptides generated from milk proteins.

A comprehensive review on bioactive peptides derived from milk and milk products of minor dairy species

“…Cholesterol esterase has been reported to be associated with the development of obesity and other related complications. Thus, in an interesting study conducted by Mudgil et al (2019), novel peptides were isolated from camel milk protein hydrolysate and then evaluated for their inhibition of cholesterol esterase. Results revealed that hydrolysate obtained by the digestion with papain exhibited the highest degree of hydrolysis.…”

Identification and characterization of cholesterol esterase and lipase inhibitory peptides from amaranth protein hydrolysates

“…These outcomes are similar to those reported by ( Nagaoka et al, 2001 ) who had previously reported the number of residues in hypocholesterolemic peptides ranges from 5 to 20. ( Baba et al, 2021 ) and ( Mudgil et al, 2019a ) have also recently reported a similar number of amino acid in the identified peptides which were predicted to possess CEase and PL inhibitory properties. Moreover, peptides (GGV, IVG, and VGVL) from the Amaranth protein reported by Soares et al (2015) demonstrated inhibition of HMG-CoA reductase enzyme, which implies a promising hypocholesterolemic effect.…”

“…Amongst the identified bioactive peptides from APHs, peptide FPFVPAPT could establish a bond with two amino acid residues present in the catalytic triad (Ser 194 and His435), and Ala108, and Phe324 which are part of an active site residue of CEase suggesting the strong inhibitory potential of this peptide against CEase. The peptides that could bind the residues of Phe324 and His435 are particularly gaining attention as CEase inhibitors, as previously reported in bioactive peptides derived from camel milk protein hydrolysates ( Mudgil et al, 2019a ) and camel whey protein hydrolysates ( Baba et al, 2021 ).

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“…The CEase inhibition was determined as per the method described by Mudgil et al (2019a) with slight modification. APHs samples (50 μL) were incubated with 5 mM p-nitrophenyl butyrate (50 μL) in sodium phosphate buffer (100 mM; pH 7.2 containing 100 mM NaCl) in a 96-well microplate.…”

“…In addition to these side effects, these medicines are also not affordable for a lot of people in developing countries. Considering these concerns and limitations with synthetic drugs, it is important to identify natural compounds with anti- hypercholesterolemic properties ( Birari and Bhutani, 2007 , Mudgil et al, 2019a ).…”