Hydrogen gas evolution and carbon dioxide fixation with visible light by chlorophyllin coupled with polyethylene glycol.
Chlorophyllin a was conjugated with alpha-(3-aminopropyl)-omega-methoxypoly(oxyethylene), PEG-NH(2), to form the PEG-chlorophyllin conjugate through acid-amide bonds. The PEG-chlorophyllin conjugate was stable toward light illumination under anaerobic condition in comparison with chlorophyllin a. The conjugate catalyzed the reduction of methyl viologen in the presence of 2-mercaptoethanol and the evolution of hydrogen gas in the presence of methyl viologen (an electron carrier), 2-mercaptoethanol (an electron donor) and hydrogenase (Scheme 1). Furthermore, the PEG-chlorophyllin conjugate 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 the PEG-chlorophyllin conjugate under the illumination, CO(2) fixation was accomplished by the synthesis of malate (C(4)) from pyruvate (C(3)) and CO(2) in the presence of malic enzyme (Scheme 2). These reactions mentioned above did never proceed in dark or without each enzyme.
Itoh
T
T
Toin Human Science and Technology Center, Department of Biomedical Engineering, Toin University of Yokohama, Kurogane-cho, Aoba-ku, Yokohama 225-8502 Japan.
Asada
H
H
Tobioka
K
K
Kodera
Y
Y
Matsushima
A
A
Hiroto
M
M
Nishimura
H
H
Kamachi
T
T
Okura
I
I
Inada
Y
Y
D000693:Anaerobiosis; D001205:Ascorbic Acid / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry*; D002735:Chlorophyllides / Q000737:chemistry*; D004355:Drug Stability; D005287:Ferredoxin-NADP Reductase / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D009243:NAD / Q000737:chemistry; D009249:NADP / Q000737:chemistry; D010084:Oxidation-Reduction; D010269:Paraquat / Q000737:chemistry; D010777:Photochemistry; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*
D002735:Chlorophyllides; D009243:NAD; D002245:Carbon Dioxide; D011092:Polyethylene Glycols; D009249:NADP; D006859:Hydrogen; D005287:Ferredoxin-NADP Reductase; C007020:chlorophyllin; D010269:Paraquat; D001205:Ascorbic Acid