IUBMB Enzyme Nomenclature


Accepted name: β-galactosidase

Reaction: Hydrolysis of terminal non-reducing β-D-galactose residues in β-D-galactosides

Other name(s): lactase; β-lactosidase; maxilact; hydrolact; β-D-lactosidase; S 2107; lactozym; trilactase; β-D-galactanase; oryzatym; sumiklat

Systematic name: β-D-galactoside galactohydrolase

Comments: Some enzymes in this group hydrolyse α-L-arabinosides; some animal enzymes also hydrolyse β-D-fucosides and β-D-glucosides; cf. EC lactase.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9031-11-2


1. Blakely, J.A. and MacKenzie, S.L. Purification and properties of a β-hexosidase from Sporobolomyces singularis. Can. J. Biochem. 47 (1969) 1021-1025. [PMID: 5389663]

2. Kuby, S.A. and Lardy, H.A. Purification and kinetics of β-D-galactosidase from Escherichia coli, strain K-12. J. Am. Chem. Soc. 75 (1953) 890-896.

3. Kuo, C.H. and Wells, W.W. β-Galactosidase from rat mammary gland. Its purification, properties, and role in the biosynthesis of 6β-O-D-galactopyranosyl myo-inositol. J. Biol. Chem. 253 (1978) 3550-3556. [PMID: 418065]

4. Landman, O.E. Properties and induction of β-galactosidase in Bacillus megaterium. Biochim. Biophys. Acta 23 (1957) 558-569.

5. Llanillo, M., Perez, N. and Cabezas, J.A. β-Galactosidase and β-glucosidase activities of the same enzyme from rabbit liver. Int. J. Biochem. 8 (1977) 557-564.

6. Monod, J. and Cohn, M. La biosynthèse induite des enzymes (adaptation enzymatique). Adv. Enzymol. Relat. Subj. Biochem. 13 (1952) 67-119.

7. Wallenfels, K. and Malhotra, O.P. in Boyer, P.D., Lardy, H. and Myrbäck, K. (Eds.), The Enzymes, 2nd edn., vol. 4, Academic Press, New York, 1960, pp. 409-430.

8. Asp, N.G., Dahlqvist, A. and Koldovský, O. Human small-intestinal β-galactosidases. Separation and characterization of one lactase and one hetero β-galactosidase. Biochem. J. 114 (1969) 351-359. [PMID: 5822067]

[EC created 1961, modified 1980]

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