Enzymatic oxidation of beta-apo-8'-carotenol to beta-apo-14'-carotenal by an enzyme different from beta-carotene-15,15'-dioxygenase.
Extracts of rat and rabbit intestinal mucosa were fractionated with ammonium sulfate. The precipitate contained beta-apocarotenoid-14',13'-dioxygenase (ADO) activity. beta-Apo-14'-carotenal was found to be the product of enzymatic cleavage of beta-apo-8'-carotenol. Activities of ADO and beta-carotene-15,15'-dioxygenase (CDO) were detected in the presence of thiols and were inactivated by 1,10-phenanthroline. Optimal pH values were 7.0 for ADO and 8.0 for CDO. Heating at 52 degrees C inhibited ADO by 70% and produced no effect on CDO. ADO activity was maximal in the presence of sodium cholate or 3-[(3-cholamidopropyl)-dimethyl-ammonio]-1-propanesulfonate (CHAPS). Sodium dodecylsulfate was required for maximal CDO activity. Proteins with ADO activity were not retained by phenyl-Sepharose CL-4B. CDO activity was eluted from columns only in the presence of detergents. The data suggest that the enzymes that catalyze the oxidative cleavage of beta-carotene to yield retinal are different from those that cleave beta-apo-8'-carotenol to yield beta-apo-14'-carotenal.
Dmitrovskii
A A
AA
Bakh Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia. inbio@glas.aps.org
Gessler
N N
NN
Gomboeva
S B
SB
Ershov YuV
Bykhovsky VYa
D000818:Animals; D002338:Carotenoids / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism*; D002847:Chromatography, Agarose; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000201:enzymology; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D050559:beta-Carotene 15,15'-Monooxygenase
C493357:Bco1 protein, rat; C110027:beta-apocarotenoid-14',13'-dioxygenase; D002338:Carotenoids; C071311:beta-apo-14'-carotenal; D010105:Oxygenases; D050559:beta-Carotene 15,15'-Monooxygenase; C004984:apocarotenal