A RasMol study of the Mechanism of Inhibition of Cysteine Endopeptidase Enzyme Papain

Cysteine endopeptidases regulate many physiological processes in the body and their impaired function may lead to several diseases. One of the methods of treating such diseases is achieved by controlling the proteolytic activity of these enzymes by using enzyme inhibition. This manuscript focuses on the mechanism of action of Papain, a cysteine endopeptidase enzyme and its inhibition using images generated with RasMol, which is one of the most popular graphics programs for the display of macromolecules like proteins and nucleic acid structures. The location of active site residues on the papain enzyme molecule is described with the RasMol images and the mode of inhibition of these active sites is described in reference with few examples of papain inhibitors. Thus, the manuscript discusses the use of RasMol program to understand the inhibition of cysteine endopeptidase enzyme papain.