| Type: | Family | Name: | Lycopene cyclase |
| Description: | Lycopene cyclases generate provitamin A carotenoids which are essential building blocks for cyclic xanthophylls involved in photosynthesis and regulatory networks. The cyclization of lycopene is the final step in carotenoid biosynthesis and may proceed via one of two pathways: the formation of a beta ring by beta-cyclase, or an epsilon ring by epsilon-cyclase. Epsilon-cyclase adds only one ring, forming the monocyclic delta-carotene, whereas beta-cyclase introduces a ring at both ends of lycopene to form the bicyclic beta-carotene []. Lycopene cyclases are widely distributed across taxonomic groups and have structural diversity. Four partly related families of lycopene cyclases are known: CrtY, CrtL (beta-ionone end group producing), CrtL (eta-ionone end group producing) and CrtL (capsanthin/capsorubin synthase).This family consists of several bacterial Lycopene cyclase (CrtY) proteins. Lycopene cyclase is a key enzyme which converts the acyclic carotenoid lycopene into the cyclic carotenoid beta-carotene []. It is thought that CrtY lycopene cyclases use reduced flavin adenine dinucleotide (redFAD) as a cofactor, which provides stabilisation of a positively charged or partially positively charged intermediate []. Lycopene cyclase is a non-redox flavoprotein. | Short Name: | CrtY |
