EC 18.104.22.168 - 7-methylxanthosine synthase
IntEnz Enzyme Nomenclature
15025 [IUBMB]S-adenosyl-L-methionineS-adenosyl-L-methionineName origin: UniProt - CHECKED (C)Formula: C15H23N6O5S
Charge: 1ChEBI compound status: CHECKED (C)xanthosinexanthosineName origin: UniProt - CHECKED (C)Formula: C10H12N4O6
Charge: 0ChEBI compound status: CHECKED (C)=7-methylxanthosine7-methylxanthosineName origin: UniProt - CHECKED (C)Formula: C11H15N4O6
Charge: 1ChEBI compound status: CHECKED (C)
The enzyme is specific for xanthosine, as XMP and xanthine cannot act as substrates [2,4]. The enzyme does not have N1- or N3- methylation activity . This is the first methylation step in the production of caffeine.
Links to other databases
The role of xanthosine in the biosynthesis of caffeine in coffee plants.Agric. Biol. Chem. 49: 2221-2222 (1985).
The first committed step reaction of caffeine biosynthesis: 7-methylxanthosine synthase is closely homologous to caffeine synthases in coffee (Coffea arabica L.).FEBS Lett. 547: 56-60 (2003). [PMID: 12860386]
Molecular cloning and functional characterization of three distinct N-methyltransferases involved in the caffeine biosynthetic pathway in coffee plants.Plant Physiol. 132: 372-380 (2003). [PMID: 12746542]
Substrate specificity of N-methyltransferase involved in purine alkaloids synthesis is dependent upon one amino acid residue of the enzyme.Mol. Genet. Genomics 275: 125-135 (2006). [PMID: 16333668]
[EC 22.214.171.124 created 2007]