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Distinct photorespiratory reactions are preferentially catalyzed by glutamate:glyoxylate and serine:glyoxylate aminotransferases in rice

Paper ID Volume ID Publish Year Pages File Format Full-Text
29789 44440 2015 8 PDF Available
Title
Distinct photorespiratory reactions are preferentially catalyzed by glutamate:glyoxylate and serine:glyoxylate aminotransferases in rice
Abstract

•The genes encoding GGAT and SGAT in rice were defined.•There are significant differences between GGAT and SGAT in enzymatic characterization.•GGAT and SGAT perform distinct reactions in photorespiration.

The metabolic function of glutamate:glyoxylate aminotransferase (GGAT) and serine:glyoxylate aminotransferase (SGAT) for photorespiration is still not exactly understood so far though it is mostly held that both enzymes may work in parallel in the reaction of glyoxylate to glycine during photorespiration of plants. Here, for the first time, we define the genes encoding GGAT and SGAT and report their biochemical and enzymatic properties in rice plants, in contrast to those from other plant species. Noticeably, GGAT exhibited approximately 18 fold higher catalytic efficiency (Kcat/Km) with glyoxylate and glutamate than SGAT with glyoxylate and serine, and additionally, rice leaves usually contain 3–4 times higher abundance of glutamate relative to serine, implicating that GGAT may preferentially utilize glyoxylate to form glycine over SGAT. When SGAT or GGAT activity was regulated by gene transformation or nitrogen deficiency, respectively, it was observed that the glycine content was positively related to GGAT activities, while both serine and glycine contents were negatively related to SGAT activities. The results suggest that GGAT preferentially catalyzes the conversion of glyoxylate into glycine while SGAT is mainly responsible for the transamination reaction of serine to hydroxypyruvate in the photorespiratory pathway of rice.

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Distinct photorespiratory reactions are preferentially catalyzed by glutamate:glyoxylate and serine:glyoxylate aminotransferases in rice
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 142, January 2015, Pages 110–117
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us