Biotechnological production and applications of ribonucleases

Abstract Ribonucleases (RNases) are small molecules, which are highly cytotoxic in nature. RNase is a type of nuclease that catalyzes the degradation of cellular RNA into smaller oligonucleotides and mononucleotides. The cytotoxic properties of RNases comprise degradation of RNA that leads to blockage of protein synthesis and induction of apoptosis in malignant cells. RNases (Binase, Barnase, RNase Sa, RNase P etc) exert cytotoxic activity on cancerous cells selectively by involving different cellular pathways. They also boost the cytotoxic effect by chemical modification or mutation. The properties such as catalytic activity, stability, non-selective nature of inhibitors, positive charge on molecule and internalization affect the cytotoxicity of the RNase. General mechanism of cytotoxic effect involves the interaction of different RNase with the cellular membrane of target cell by nonspecific interactions mediated by receptor Globo H, Columbic forces, internalization by endocytosis, translocation to the cytosol and degradation of cellular RNA which eventually lead to cell death. The present chapter highlights the mechanism(s) of cytotoxicity of RNases toward the cancerous cells, which make(s) RNases prominent chemotherapeutic or anticancer agents.