Substrate specificity of a recombinant chicken beta-carotene 15,15'-monooxygenase that converts beta-carotene into retinal.
The recombinant beta-carotene 15,15'-monooxygenase from chicken liver was purified as a single 60 kDa band by His-Trap HP and Resource Q chromatography. It had a molecular mass of 240 kDa by gel filtration indicating the native form to be tetramer. The enzyme converted beta-carotene under maximal conditions (pH 8.0 and 37 degrees C) with a k (cat) of 1.65 min(-1) and a K (m) of 26 muM and its conversion yield of beta-carotene to retinal was 120% (mol mol(-1)). The enzyme displayed catalytic efficiency and conversion yield for beta-carotene, beta-cryptoxanthin, beta-apo-8'-carotenal, beta-apo-4'-carotenal, alpha-carotene and gamma-carotene in decreasing order but not for zeaxanthin, lutein, beta-apo-12'-carotenal and lycopene, suggesting that the presence of one unsubstituted beta-ionone ring in a substrate with a molecular weight greater than C(30) seems to be essential for enzyme activity.
Kim
Yeong-Su
YS
Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, South Korea.
Oh
Deok-Kun
DK
D000818:Animals; D002645:Chickens; D002850:Chromatography, Gel; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D045792:Norisoprenoids / Q000378:metabolism; D055503:Protein Multimerization; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012172:Retinaldehyde / Q000378:metabolism*; D013379:Substrate Specificity; D019207:beta Carotene / Q000378:metabolism*; D050559:beta-Carotene 15,15'-Monooxygenase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D045792:Norisoprenoids; D021122:Protein Subunits; D011994:Recombinant Proteins; D019207:beta Carotene; C008157:beta-ionone; D050559:beta-Carotene 15,15'-Monooxygenase; D012172:Retinaldehyde