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Glutamate synthesis via photoreduction of NADP + by photostable chlorophyllide coupled with polyethylene‐glycol
Author(s) -
Asada Hideharu,
Itoh Tetsuji,
Kodera Yoh,
Matsushima Ayako,
Hiroto Misao,
Nishimura Hiroyuki,
Inada Yuji
Publication year - 2001
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.1029
Subject(s) - chemistry , conjugate , photochemistry , polyethylene glycol , peg ratio , glutamate dehydrogenase , nad+ kinase , stereochemistry , enzyme , organic chemistry , biochemistry , glutamate receptor , mathematical analysis , receptor , mathematics , finance , economics
Chlorophyllide a was coupled with α‐(3‐aminopropyl)‐ω‐methoxypoly(oxyethylene) (PEG–NH 2 ) 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 NH 4 + 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. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 86–90, 2001.