50281-38-4Relevant articles and documents
Absolute configurational assignment of 3-hydroxycarotenoids
Andersson, Thomas,Borhan, Babak,Berova, Nina,Nakanishi, Koji,Haugan, Jarle Andre,Liaaen-Jensen, Synnove
, p. 2409 - 2414 (2000)
Attempts were made to develop an exciton chirality method applicable to the unique cases represented by 3-hydroxycarotenoids. However, this approach has so far not been successful. The 3-hydroxy configurations were therefore determined by the extended Mosher 1H-NMR method. Nine carotenoids with seven different end groups and of known 3-hydroxy configurations were derivatized with (R)- and (S)-methoxyphenylacetic acid (MPA); they all gave the expected shift differences. Three other auxiliary reagents with naphthalene and anthracene nuclei gave larger and consistent NMR shift differences, but they are not yet commercially available.
The human mitochondrial enzyme BCO2 exhibits catalytic activity toward carotenoids and apocarotenoids
Thomas, Linda D.,Bandara, Sepalika,Parmar, Vipulkumar M.,Srinivasagan, Ramkumar,Khadka, Nimesh,Golczak, Marcin,Kiser, Philip D.,von Lintig, Johannes
, p. 15553 - 15565 (2020/12/09)
The enzyme b-carotene oxygenase 2 (BCO2) converts carotenoids into more polar metabolites. Studies in mammals, fish, and birds revealed that BCO2 controls carotenoid homeostasis and is involved in the pathway for vitamin A production. However, it is controversial whether BCO2 function is conserved in humans, because of a 4-amino acid long insertion caused by a splice acceptor site polymorphism. We here show that human BCO2 splice variants, BCO2a and BCO2b, are expressed as pre-proteins with mitochondrial targeting sequence (MTS). The MTS of BCO2a directed a green fluorescent reporter protein to the mitochondria when expressed in ARPE-19 cells. Removal of the MTS increased solubility of BCO2a when expressed in Escherichia coli and rendered the recombinant protein enzymatically active. The expression of the enzymatically active recombinant human BCO2a was further improved by codon optimization and its fusion with maltose-binding protein. Introduction of the 4-amino acid insertion into mouse Bco2 did not impede the chimeric enzyme’s catalytic proficiency. We further showed that the chimeric BCO2 displayed broad substrate specificity and converted carotenoids into two ionones and a central C14-apocarotendial by oxidative cleavage reactions at C9,C10 and C9’,C10’. Thus, our study demonstrates that human BCO2 is a catalytically competent enzyme. Consequently, information on BCO2 becomes broadly applicable in human biology with important implications for the physiology of the eyes and other tissues.
The Oxidation of Hydrophobic Aromatic Substrates by Using a Variant of the P450 Monooxygenase CYP101B1
Sarkar, Md. Raihan,Lee, Joel H. Z.,Bell, Stephen G.
, p. 2119 - 2128 (2017/10/12)
The cytochrome P450 monooxygenase CYP101B1, from a Novosphingobium bacterium is able to bind and oxidise aromatic substrates but at a lower activity and efficiency than norisoprenoids and monoterpenoid esters. Histidine 85 of CYP101B1 aligns with tyrosine 96 of CYP101A1, which, in the latter enzyme forms the only hydrophilic interaction with its substrate, camphor. The histidine residue of CYP101B1 was mutated to phenylalanine with the aim of improving the activity of the enzyme for hydrophobic substrates. The H85F mutant lowered the binding affinity and activity of the enzyme for β-ionone and altered the oxidation selectivity. This variant also showed enhanced affinity and activity towards alkylbenzenes, styrenes and methylnaphthalenes. For example the rate of product formation for acenaphthene oxidation was improved sixfold to 245 nmol per nmol CYP per min. Certain disubstituted naphthalenes and substrates, such as phenylcyclohexane and biphenyls, were oxidised with lower activity by the H85F variant. Variants at H85 (A and G) designed to introduce additional space into the active site so as to accommodate these larger substrates did not improve the oxidation activity. As the H85F mutant of CYP101B1 improved the oxidation of hydrophobic substrates, this residue is likely to be in the substrate binding pocket or the access channel of the enzyme. The side chain of the histidine might interact with the carbonyl groups of the favoured norisoprenoid substrates of CYP101B1.
Total synthesis of (±)-3-hydroxy-β-ionone through a ring-closing enyne metathesis
Kikuchi, Daisuke,Yoshida, Masahiro,Shishido, Kozo
, p. 577 - 580 (2012/04/11)
The total synthesis of (±)-3-hydroxy - ionone, a bisnor-sesquiterpene having allelopathic activity, has been accomplished employing an enyne metathesis for the construction of the C1-C8 segment and two-carbon elongation via a nitrile oxide-alkene [3+2] cycloaddition as the key steps. Georg Thieme Verlag Stuttgart · New York.
