This family includes heparin lyase I, EC:4.2.2.7. Heparin lyase I depolymerises heparin by cleaving the glycosidic linkage next to an iduronic acid moiety [1,2]. The structure of heparin lyase I consists of a beta-jelly roll domain with a long, deep substrate-binding groove and an unusual thumb domain containing many basic residues extending from the main body of the enzyme [2]. This family also includes glucuronan lyase, EC:4.2.2.14 [3]. The structure glucuronan lyase is a beta-jelly roll [4].

1: Expression in Escherichia coli, purification and characterization of heparinase I from Flavobacterium heparinum. Ernst S, Venkataraman G, Winkler S, Godavarti R, Langer R, Cooney CL, Sasisekharan R; Biochem J. 1996;315:589-597. PMID:8615834

2: Structural snapshots of heparin depolymerization by heparin lyase I. Han YH, Garron ML, Kim HY, Kim WS, Zhang Z, Ryu KS, Shaya D, Xiao Z, Cheong C, Kim YS, Linhardt RJ, Jeon YH, Cygler M; J Biol Chem. 2009;284:34019-34027. PMID:19801541

3: Cloning of the Trichoderma reesei cDNA encoding a glucuronan lyase belonging to a novel polysaccharide lyase family. Konno N, Igarashi K, Habu N, Samejima M, Isogai A; Appl Environ Microbiol. 2009;75:101-107. PMID:18978091

4: Crystal structure of polysaccharide lyase family 20 endo-beta-1,4-glucuronan lyase from the filamentous fungus Trichoderma reesei. Konno N, Ishida T, Igarashi K, Fushinobu S, Habu N, Samejima M, Isogai A; FEBS Lett. 2009;583:1323-1326. PMID:19306878