Glutamate synthesis via photoreduction of NADP+ by photostable chlorophyllide coupled with polyethylene-glycol.
Chlorophyllide a was coupled with alpha-(3-aminopropyl)-omega-methoxypoly(oxyethylene) (PEG-NH2) to form a PEG-chlorophyllide conjugate through an acid-amide bond. The conjugate catalyzed the reduction of methylviologen in the presence of 2-mercaptoethanol. It also catalyzed the photoreduction of NADP+ or NAD+ in the presence of ascorbate as an electron donor and ferredoxin-NADP+ reductase as the coupling enzyme. Utilizing the reducing power of NADPH generated by PEG-chlorophyllide conjugate under illumination, glutamate was synthesized from 2-oxoglutarate and NH4+ in the presence of glutamate dehydrogenase. PEG-chlorophyllide conjugate was quite stable toward light illumination compared with chlorophyll a. The increase in the molecular weight of PEG in the PEG-chlorophyllide conjugates was accompanied by the enhancement of photostability of the conjugate and also by the increased solubility in the aqueous solution.
Asada
H
H
Toin Human Science and Technology Center and Department of Biomedical Engineering, Toin University of Yokohama, Kurogane-cho, Aoba-ku, Yokohama 225-8502 Japan.
Itoh
T
T
Kodera
Y
Y
Matsushima
A
A
Hiroto
M
M
Nishimura
H
H
Inada
Y
Y
D002265:Carboxylic Ester Hydrolases; D002735:Chlorophyllides; D004355:Drug Stability; D005287:Ferredoxin-NADP Reductase / Q000378:metabolism; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D018698:Glutamic Acid / Q000096:biosynthesis / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D007656:Ketoglutaric Acids; D007700:Kinetics; D008027:Light; D019684:Magnoliopsida / Q000201:enzymology; D008623:Mercaptoethanol; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D011092:Polyethylene Glycols / Q000138:chemical synthesis; D012441:Saccharomyces cerevisiae / Q000201:enzymology
D002735:Chlorophyllides; D007202:Indicators and Reagents; D007656:Ketoglutaric Acids; C434384:polyethylene glycol-chlorophyllide conjugate; D009243:NAD; C034388:chlorophyllide a; D018698:Glutamic Acid; D011092:Polyethylene Glycols; D009249:NADP; D008623:Mercaptoethanol; D005287:Ferredoxin-NADP Reductase; D005969:Glutamate Dehydrogenase; D002265:Carboxylic Ester Hydrolases; C019875:chlorophyllase