Papain, a Plant Enzyme of Biological Importance: A Review

Abstract

Papain is a plant proteolytic enzyme for the cysteine proteinase family cysteine protease enzyme in which enormous progress has been made to understand its functions. Papain is found naturally in papaya (Carica papaya L.) manufactured from the latex of raw papaya fruits. The enzyme is able to break down organic molecules made of amino acids, known as polypeptides and thus plays a crucial role in diverse biological processes in physiological and pathological states, drug designs, industrial uses such as meat tenderizers and pharmaceutical preparations. The unique structure of papain gives it the functionality that helps elucidate how proteolytic enzymes work and also makes it valuable for a variety of purposes. In the present review, its biological importance, properties and structural features that are important to an understanding of their biological function are presented. Its potential for production and market opportunities are also discussed.

Chemical Analysis of <i>Carica papaya</i> L. Crude Latex

“…Papain occurs in all parts of the tree except the root [40]. A well managed papaya production has re-corded higher papain yield of 8.17 g·fruit −1 and highest papain of 686.29 g·plant −1 in a period of 6 mo [35]. As to the analysis of the protease activity, results showed that papain at pH 5.5 had a protease activity of 2655 units·g −1 and 285 units·g −1 only at pH 9.0 ( Table 2).…”

“…Cysteine protease enzyme is found naturally in papaya (C. papaya L.) manufactured from the latex of raw papaya fruits. The enzyme is able to break down organic molecules made of amino acids, known as polypeptides and thus plays a crucial role in diverse biological processes in physiological and pathological states, drug designs and industrial uses [35] and the enzyme is the most thoroughly characterized of the thiol proteinases [36]. Papain has revealed to be an enzymatic protein of significant biological and economic importance, since the unique structure of papain provides functionality and helps explain how this proteolytic enzyme works and makes it valuable for a variety of purposes [35].…”

“…The enzyme is able to break down organic molecules made of amino acids, known as polypeptides and thus plays a crucial role in diverse biological processes in physiological and pathological states, drug designs and industrial uses [35] and the enzyme is the most thoroughly characterized of the thiol proteinases [36]. Papain has revealed to be an enzymatic protein of significant biological and economic importance, since the unique structure of papain provides functionality and helps explain how this proteolytic enzyme works and makes it valuable for a variety of purposes [35]. This proteolytic enzyme usually consists of two well-defined domains which provide an excellent system for studies in understanding the folding-unfolding behavior of proteins [37].…”

“…Its three-dimensional structure consists of two distinct structural domains with a cleft between them. This cleft contains the active site, which contains a catalytic diad that has been likened to the catalytic triad of chymotrypsin [35]. Papain occurs in all parts of the tree except the root [40].…”

Papaya (Carica papaya) latex- an alternative to rennet for cottage cheese preparation

“…It requires a free sulfhydryl group for its catalytic activity. The papain, a photolytic enzyme isolated from papaya latex is capable to break down polypeptides which are organic molecule consist of amino acids (Amri and Mamboya, 2012).…”