ISSN:
1432-2048
Keywords:
Key words:Arabidopsis– Insect cell cultures – Jasmonate biosynthesis – 12-Oxophytodienoate reductase (overexpression) – 12-Oxophytodienoate reductase (stereospecificity)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract. In addition to OPR1 and OPR2, two isoenzymes of 12-oxophytodienoate reductase, a third isoform (OPR3) has recently been identified in Arabidopsis thaliana (L.) Heynh. The expression of the OPR3 gene is induced not only by a variety of stimuli, such as touch, wind, wounding, UV-light and application of detergent, but also by brassinosteroids. The three enzymes were expressed in a functional form in Escherichia coli, and OPR2 was additionally expressed in insect cell cultures and overexpressed in A. thaliana. Substrate conversion was analyzed using a stereospecific assay. The results show that OPR3 effectively converts the natural (9S,13S)-12-oxophytodienoic acid [K m = 35 μM, V max 53.7 nkat (mg protein)−1] to the corresponding 3-2(2′(Z)-pentenyl) cyclopentane-1-octanoic acid (OPC-8:0) stereoisomer while OPR1 and OPR2 convert (9S,13S)-12-oxophytodienoic acid with greatly reduced efficiency compared to OPR3. Thus, OPR3 is the isoenzyme relevant for jasmonate biosynthesis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004250050706
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