Publications

• Biochemical characterization of purified zeta-carotene desaturase from Anabaena PCC 7120 after expression in Escherichia coli.

  Albrecht M., Linden H., Sandmann G.

  A novel enzyme, zeta-carotene desaturase from the cyanobacterium Anabaena, which catalyzes the last two steps in a series of desaturations, was overexpressed in Escherichia coli. For the first time, this allowed the purification of this enzyme and subsequent enzyme kinetic studies. The enzyme was ... >> More

  A novel enzyme, zeta-carotene desaturase from the cyanobacterium Anabaena, which catalyzes the last two steps in a series of desaturations, was overexpressed in Escherichia coli. For the first time, this allowed the purification of this enzyme and subsequent enzyme kinetic studies. The enzyme was solubilized from the E. coli membranes by Chaps and purified to homogeneity by ammonium sulfate precipitation, ion-exchange and hydrophobic interaction chromatography. The correct translational start was confirmed by N-terminal protein sequencing. Substrates for zeta-carotene desaturase apart from zeta-carotene are those carotenes which partially resemble the latter, like neurosporene and beta-zeacarotene yielding lycopene and gamma-carotene, respectively as reaction products. Also cis isomers like pro-zeta-carotene were converted to the corresponding products. Km values of 10 microM were determined for both substrates zeta-carotene and neurosporene. The enzyme was inhibited to some extent by the experimental herbicides J852 and LS80707 and also by diphenylamine which is a well-known inhibitor of the bacterial-type phytoene desaturase. << Less

  Eur J Biochem 236:115-120(1996) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• zeta-Carotene cis isomers as products and substrates in the plant poly-cis carotenoid biosynthetic pathway to lycopene.

  Breitenbach J., Sandmann G.

  The plant carotenoid biosynthetic pathway to cyclic carotenes proceeds via carotene precursors in cis configuration. Involvement of individual isomers was elucidated by genetic complementation of desaturations and in vitro reactions of the corresponding enzyme. Determination of substrate and produ ... >> More

  The plant carotenoid biosynthetic pathway to cyclic carotenes proceeds via carotene precursors in cis configuration. Involvement of individual isomers was elucidated by genetic complementation of desaturations and in vitro reactions of the corresponding enzyme. Determination of substrate and product specificity of phytoene and zeta-carotene desaturase revealed that 15-cis-phytoene is converted to 9,15,9'-tricis-zeta-carotene with 15,9'-dicis-phytofluene as intermediate by the first desaturase. Prior to a subsequent conversion by zeta-carotene desaturase, the 15-cis double bond of 9,15,9'-tricis-zeta-carotene has to be (photo)isomerized to all-trans. Then, the resulting 9,9'-dicis-zeta-carotene is utilized by zeta-carotene desaturase via 7,9,9'-tricis-neurosporene to 7,9,7',9'-tetracis-lycopene. Other zeta-carotene isomers that are assumed to be spontaneous isomerization products were not converted, except for the asymmetric 9-cis-zeta-carotene. This isomer is desaturated only to 7,9-dicis-neurosporene resembling a dead-end of the pathway. Prolycopene, the product of the desaturation reactions, is finally isomerized by a specific isomerase to all-trans-lycopene, which is a prerequisite for cyclization to beta-carotene. The 5-cis-lycopene and the 9-cis-and 13-cis-beta-carotene isomers detected in leaves are thought to originate independently from cis precursors by non-enzymatic isomerization of their all-trans forms. << Less

  Planta 220:785-793(2005) [PubMed] [EuropePMC]

  This publication is cited by 8 other entries.