Hydroxymethylpyrimidine kinase

Hydroxymethylpyrimidine kinase (EC 2.7.1.49) is an enzyme that catalyzes the chemical reaction

The enzyme characterised from baker's yeast converts toxopyrimidine to 4-amino-2-methyl-5-phosphooxymethylpyrimidine by transferring a phosphate group from the cofactor, adenosine triphosphate (ATP), which is converted to adenosine diphosphate (ADP). This reaction is a step in the biosynthesis of thiamine (vitamin B₁).^[1][2]

This enzyme is a transferases, specifically one transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:4-amino-5-hydroxymethyl-2-methylpyrimidine 5-phosphotransferase. This enzyme is also called hydroxymethylpyrimidine kinase (phosphorylating).^[3]