Proteins can be a valuable source of peptides with the antihypertensive, antiamnestic, antithrombotic, immunomodulating etc. activity. Bovine ß- lactoglobulin - one of whey milk proteins is regarded as the one of the richest sources of bioactive peptides. The structural similarity of bovine ß- lactoglobulin indicates that the protein belongs to a lipocalin family. Among lipocalins the following proteins can be found: retinol binding protein (RBP), bilin binding protein (BBP), epidermal retinol binding protein (EBP) or odorant binding protein (OBP). In all members of lipocalin family the common motifs are A-B, B-C, D-E, E-F, F-G, G-H loops as well as the fragments ß-A, ß-B, ß-C, ß-D, ß-E, ß-F, ß-H, and ß-I. Lipocalins with other structural families like avidins, fatty acid binding proteins (FABs) are the part of structural superfamily i.e calycins.
This paper presents computer-aided analysis of 5 proteins belonging to lipocalin family carried out with the help of database containing 1,100 bioactive peptide sequences. The results have shown that the most of bioactive sequences in all analysed lipocalins were observed in fragments of structures ß-A, ß-G, ß-I and A-B loop. In the above -mentioned motifs the fragments with the following biological activity were found: antihypertensive, opioid, immunomodulating, dipeptidyl peptidase inhibitors, antiamnestic, antithrombotic, stomach mucosal membrane regulating and neuropeptides. Bioactive fragments found in loops were located outside of the protein molecule and fragments found in ß structures inside of it. Such iformation may be meaningful in designing of proteolytic processes in aspect of obtaining the bioactive peptides on industrial scale.
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