EFFECT OF PHOSPHATE RESIDUE OF NADPH ON THE INTERACTION BETWEEN CATALYTIC DOMAINS OF A MULTIFUNCTIONAL POLYKETIDE SYNTHETIC ENZYME 6-HYDROXYMELLEIN SYNTHASE
F. Kurosaki, EFFECT OF PHOSPHATE RESIDUE OF NADPH ON THE INTERACTION BETWEEN CATALYTIC DOMAINS OF A MULTIFUNCTIONAL POLYKETIDE SYNTHETIC ENZYME 6-HYDROXYMELLEIN SYNTHASE, Biochimica et biophysica acta. Bioenergetics, 1363(1), 1998, pp. 6-10
Association of NADPH with the ketoreducing domain of 6-hydroxymellein
synthase, a multifunctional polyketide synthetic enzyme of carrot, evo
ked the alternation of microstructure around the primary binding site
of the co-substrates acetyl-and malonyl-CoAs, and this resulted in the
marked decrease in K-m value of the enzyme protein for acetyl-CoA. Ln
contrast, the enzyme did not show the increase in the affinity to the
substrate when NADPH was replaced by NADH. These results suggest that
the phosphate residue attached to 2'-position of adenosyl moiety of N
ADPH molecule plays an important role in the co-operative interaction
between these functional domains of the synthase. (C) 1998 Elsevier Sc
ience B.V.