Function
Prenyltransferase that mediates the formation of menaquinone-4 (MK-4), a vitamin K2 isoform, thereby acting as a mitochondrial electron carrier. Mediates the conversion of phylloquinone (PK) into MK-4, probably by cleaving the side chain of phylloquinone (PK) to release 2-methyl-1,4-naphthoquinone (menadione; K3) and then prenylating it with geranylgeranyl pyrophosphate (GGPP) to form MK-4. MK-4 acts as a membrane electron carrier downstream of a electron transport chain complex, improving mitochondrial oxygen consumption.
Sequence
MATSSQLLPNGNLSRNGKTKTEDGEEVEAVVGARAAGADAGVALTGRLTGHPSTSGTFMKLKTYLLALRPWSLSASLVPTLLGSALAYRSQWAEEFSLATFFLTAFTVVTVHCAGNVVNTYFDFIKGIDKQKADDRTLVDHILTKDEVVSLGAILYMAGCGGFVLLAVLSPAKMEHLALIYFGGLSSSFLYTGGIGFKYIALGDLVILILFGPISVLFAFMSQTGHLDWTTMGYAIPLALNTEAILHSNNTRDADNDRRAGIVTLAILIGRTASHVLYAMLLFAPYSLFFIFGLKYSLWFLLPLVTLPQAFQIEKRFRNEQTMHLVPRQTAKLNFFFGILYVVACCCAHQLPTFGLRRN