Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

lactose synthase

Name from literature


Pathway from literature

uridine nucleotide cycle that supports lactose synthesis

Pathway from KEGG

Carbohydrate Metabolism; Galactose metabolism; map00052


Mouse (10090)

Genome localization

4 A5|4 18.6 cM[14595 ], 15 F1[16770 ], 4 D1[53418 ],


The enzyme is a complex of two proteins, A and B. In the absence of the B protein (alpha-lactalbumin), the enzyme catalyses the transfer of galactose from UDP-galactose to N-acetylglucosamine (EC N-acetyllactosamine synthase).

Rate-limiting Description

"It is, therefore, apparent that the rate-limiting component for the PRL stimulation of lactose synthesis in cultured mouse mammary tissues is galactosyl transferase activity." (1908098)

Gene ontology

Gene ontology

GO:0030198 (P) extracellular matrix organization [P15535 ];
GO:0030145 (F) manganese ion binding [Q9Z2Y2, P15535 ];
GO:0009312 (P) oligosaccharide biosynthetic process [P15535 ];
GO:0060058 (P) positive regulation of apoptosis involved i... [P15535 ];
GO:0005989 (P) lactose biosynthetic process [P15535 ];
GO:0005794 (C) Golgi apparatus [Q9Z2Y2, P15535 ];
GO:0005975 (P) carbohydrate metabolic process [Q9Z2Y2 ];
GO:0060055 (P) angiogenesis involved in wound healing [P15535 ];
GO:0048754 (P) branching morphogenesis of a tube [P15535 ];
GO:0009986 (C) cell surface [P15535 ];
GO:0007341 (P) penetration of zona pellucida [P15535 ];
GO:0016021 (C) integral to membrane [Q9Z2Y2, P15535 ];
GO:0003831 (F) beta-N-acetylglucosaminylglycopeptide beta-... [Q9Z2Y2, P15535 ];
GO:0007155 (P) cell adhesion [P15535 ];
GO:0002064 (P) epithelial cell development [P15535 ];
GO:0006496 (P) protein amino acid terminal N-glycosylation [P15535 ];
GO:0002526 (P) acute inflammatory response [P15535 ];
GO:0050900 (P) leukocyte migration [P15535 ];
GO:0008285 (P) negative regulation of cell proliferation [P15535 ];
GO:0005886 (C) plasma membrane [P15535 ];
GO:0060046 (P) regulation of acrosome reaction [P15535 ];
GO:0006012 (P) galactose metabolic process [P15535 ];
GO:0003945 (F) N-acetyllactosamine synthase activity [Q9Z2Y2, P15535 ];
GO:0005576 (C) extracellular region [P15535 ];
GO:0051270 (P) regulation of cell motion [P15535 ];
GO:0007339 (P) binding of sperm to zona pellucida [P15535 ];
GO:0060054 (P) positive regulation of epithelial cell prol... [P15535 ];
GO:0004461 (F) lactose synthase activity [Q9Z2Y2, P15535 ];
GO:0045136 (P) development of secondary sexual characteris... [P15535 ];
GO:0008092 (F) cytoskeletal protein binding [P15535 ];

Subcellular localization


extracellular matrix [P15535 ];

extracellular [P15535 ];

golgi apparatus [Q9Z2Y2, P15535 ];

membrane [Q9Z2Y2, P15535 ];



P15535; Q9Z2Y2

Entrez Gene

14595; 16770; 53418

  Copyright 2009, Center for Bioinformatics 
  Last Modified: 2009-03-24  
  Design by Zhao Min