InterPro: IPR015955 Lactate dehydrogenase/glycoside hydrolase, family 4, C-terminal

This entry represents a structural motif found at the C-terminal of lactate dehydrogenase (EC:1.1.1.27)and malate dehydrogenases (EC:1.1.1.37), as well as at the C-terminal of family 4 glycoside hydrolases (EC:3.2.1). These domains have an unusual fold consisting of segregated alpha-helical and beta-sheet regions, although they contain predominantly anti-parallel beta-sheets [1, 2, 3].

L-lactate dehydrogenases are metabolic enzymes that catalyse the conversion of L-lactate to pyruvate, the last step in anaerobic glycolysis. L-lactate dehydrogenase is also found as a lens crystallin in bird and crocodile eyes. Malate dehydrogenases catalyse the interconversion of malate to oxaloacetate. The enzyme participates in the citric acid cycle.

O-Glycosyl hydrolases EC:3.2.1. are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [4, 5, 6]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site [7]. Because the fold of proteins is better conserved than their sequences, some of the families can be grouped in 'clans'. Glycoside hydrolase family 4 GH4 comprises enzymes with several known activities; 6-phospho-beta-glucosidase (EC:3.2.1.86); 6-phospho-alpha-glucosidase (EC:3.2.1.122); alpha-galactosidase (EC:3.2.1.22).