A compound enzyme, comprising L-histidine methylase, halogen methyltransferase and trimethylhistidine sulfurylase. L-histidine is catalyzed by L-histidine methylase and halogen methyltransferase to obtain trimethylhistidine, and then is catalyzed by trimethylhistidine sulfurase to obtain the L-ergothioneine. The method can realize conversion from L-histidine to L-ergothioneine only in two steps. Moreover, SAM enzyme is regenerated, such that the usage amount of the SAM enzyme is greatly reduced. Therefore, the method greatly reduces the raw material cost. Moreover, the method is high in reaction concentration (about 30 g/L), simple in process and good in industrial production prospect.

Synthesis of enantiopure cis-?-irone from a renewable carbon source Disclosed herein are natural and synthetic enzymes capable of performing a method of producing cis-?-irone. The method comprises providing an enzyme capable of converting psi-ionone to cis-?-irone; and contacting the enzyme and psi-ionone under suitable conditions to produce cis-?-irone. The enzyme may be a methyltransferase from Streptomyces albireticuli (SaMT), a promiscuous bifunctional methyltransferase/cyclase (pMT1) enzyme from Streptomyces, or a modified pMT1 enzyme with at least one substitution. The enzymes allow the in-vivo and in-vitro production of cis-?-irone including the use of glucose as feedstock for the biotransformation into cis-?-irone.