earticle

영어

The activity of a carotenoid cleavage dioxygenase (NosCCD) in Nostoc sp. PCC7120 was biochemically and enzymologically characterized in vivo and in vitro. The highest activity of NosCCD was observed under optimum condition (pH 7.0, 37 ºC, 0.5 mM FeSO4, and Tween 40) when C30 β-apo-8’-carotenal was used as a substrate. Unlike previous reports, NosCCD cleaves the central C15-C15’ double bond as well as an excentric double bond at the C13-C14/C13’-C14’ position of C30 β- apo-8’-carotenal, forming C20 retinal, C22 β-apo-14’-carotenal and C18 β- apo-13-carotenal as cleavage products. The kinetic values of NosCCD were Km = 28 uM and Vmax = 0.28 uM/min for the β-apo-8’-carotenal. When NosCCD was coexpressed with C30 4,4’-diaponeurosporene/ 4,4’-diaponeurosporenal/4,4’-diaponeurosporen-4-oic acid biosynthetic pathways in Escherichia coli, C17 and C23 aldehyde carotenoids were detected as cleavage products, indicating those structures of carotenoids were substrates for NosCCD.