Riboflavin Kinase (RFK)

Riboflavin kinase (RFK; EC 2.7.1.26) is an essential enzyme that catalyzes the phosphorylation of riboflavin (vitamin B2) to form flavin mononucleotide (FMN), an obligatory step in vitamin B2 utilization and flavin cofactor synthesis.

The reference genome sequence contains a polymorphism that changes the upstream ATG found in most transcripts to ATT; hence the next downstream AUG is annotated. This polymorphism is represented in the Reference SNP, rs2490582. The reference genome polymorphism results in a protein that is 7 aa shorter at the N-terminus, and is supported by homologous proteins. It is also possible that leaky scanning by ribosomes would permit translation initiation from the downstream AUG in alleles containing the upstream AUG.