title: Catalytic properties of an expressed and purified higher plant type zeta-carotene desaturase from Capsicum annuum.
abstract: The zeta-carotene desaturase from Capsicum annuum (EC 1.14.99.-) was expressed in Escherichia coli, purified and characterized biochemically. The enzyme acts as a monomer with lipophilic quinones as cofactors. Km values for the substrate zeta-carotene or the intermediate neurosporene in the two-step desaturation reaction are almost identical. Product analysis showed that different lycopene isomers are formed, including substantial amounts of the all-trans form, together with 7,7',9,9'-tetracis prolycopene via the corresponding neurosporene isomers. The application of different geometric isomers as substrates revealed that the zeta-carotene desaturase has no preference for certain isomers and that the nature of the isomers formed during catalysis depends strictly on the isomeric composition of the substrate.
authors.affiliation: Botanisches Institut, Goethe Universität, Frankfurt, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Breitenbach
authors.forename: M
authors.initials: M
authors.lastname: Kuntz
authors.forename: S
authors.initials: S
authors.lastname: Takaichi
authors.forename: G
authors.initials: G
authors.lastname: Sandmann
mesh_terms: D002212:Capsicum / Q000201:enzymology* / Q000235:genetics; D002338:Carotenoids / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D007536:Isomerism; D007700:Kinetics; D000077276:Lycopene; D010088:Oxidoreductases / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010946:Plants, Medicinal; D010971:Plastoquinone / Q000031:analogs & derivatives / Q000494:pharmacology; D011994:Recombinant Proteins / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D011994:Recombinant Proteins; C085776:decylplastoquinone; D014451:Ubiquinone; D002338:Carotenoids; C008604:neurosporene; C060262:2,3-dimethoxy-5-methyl-6-decyl-1,4-benzoquinone; D010088:Oxidoreductases; C099215:zeta-carotene desaturase; D010971:Plastoquinone; D000077276:Lycopene