Computer-aided characteristics of proteins as potential precursors of bioactive peptides

Proteins, apart from their basic functions, may play the role of precursors of the peptides that regulate the body functions and/or show antihypertensive, antithrombotic, antiamnestic, immunomodulating and other activities. Computer analysis of 109 protein sequences, done with help of a database containing 109 protein sequences and 1100 bioactive peptides sequences, has been presented. Following discriminants have been used: the frequency of occurence of the bioactive fragments in a protein chain (A), potential activity of protein fragments (B) and the profile of potential biological activity of a protein. 3781 bioactive fragments present in the protein sequences under consideration have been found. Most commonly occurring bioactive fragments were angiotensin converting enzyme inhibitors (ACE) (EC 3.4.15.1.) and dipeptidyl peptidase IV inhibitors. Bovine beta-casein and rice prolamin are the best precursors of antihypertensive peptides. Bioactive fragments as well as their surroundings are hydrophilic and mostly localized at random coil structures of proteins.