ABSTRACT
Heparinases are enzymes that selectively cleave heparin and heparan sulfate chains, via cleavage of the glycosidic linkage between hexosamines and uronic acids, producing disaccharide and oligosaccharide products. While heparin is well known as an anti-coagulant drug, heparin and heparan sulfate are also involved in biological processes such as inflammation, cancer and angiogenesis and viral and bacterial infections and are of growing interest for their therapeutic potential. Recently, potential roles of heparin and heparan sulfate in relation to COVID-19 infection have been highlighted. The ability of heparinases to selectively cleave heparin chains has been exploited industrially to produce low molecular weight heparin, which has replaced heparin in several clinical applications. Other applications of heparinases include heparin and heparan sulfate structural analysis, neutralisation of heparin in blood and removal of the inhibitory effect of heparin on various enzymes. Heparinases are known to inhibit neovascularization and heparinase III is of interest for treating cancer and inhibiting tumour cell growth. Heparinase activity, first isolated from Pedobacter heparinus, has since been reported from several other microorganisms. Significant progress has been made in the production, characterisation and improvement of microbial heparinases in response to application demands in terms of heparinase yield and purity, which is likely to extend their usefulness in various applications. This review focuses on recent developments in the identification, characterisation and improvement of microbial heparinases and their established and emerging industrial, clinical and therapeutic applications.