4-Coumarate:coenzyme A ligase in black locust (Robinia pseudoacacia) catalyses the conversion of sinapate to sinapoyl-CoA.
4-Coumarate:coenzyme A (CoA) ligase (4CL, EC 6.2.1.12) in crude enzyme preparation from the developing xylem of black locust (Robinia pseudoacacia) converted sinapate to sinapoyl CoA. The sinapate-converting activity was not inhibited by other cinnamate derivatives, such as p-coumarate, caffeate or ferulate, in the mixed-substrate assay. The crude extract prepared from the developing xylem was separated by anion-exchange chromatography into three different 4CL isoforms. The isoform 4CL1 had a strong substrate preference for p-coumarate, but lacked the activity for ferulate and sinapate. On the other hand, 4CL2 and 4CL3 displayed activity toward sinapate and also possessed high activity toward caffeate as well as p-coumarate. The crude extract from the shoots exhibited a very similar substrate preference to that of the developing xylem; therefore, 4CL2 may be a major isoform in both crude enzyme preparations. These results support the hypothesis that sinapate-converting 4CL isoform is constitutively expressed in lignin-forming cells.
Hamada
Katsuyoshi
K
Department of Forest Resources Science, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan.
Nishida
Tomoaki
T
Yamauchi
Kazuchika
K
Fukushima
Kazuhiko
K
Kondo
Ryuichiro
R
Tsutsumi
Yuji
Y
D000214:Acyl Coenzyme A / Q000096:biosynthesis; D003066:Coenzyme A Ligases / Q000302:isolation & purification / Q000378:metabolism*; D003373:Coumaric Acids / Q000378:metabolism; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism; D008031:Lignin / Q000096:biosynthesis; D031301:Robinia / Q000201:enzymology* / Q000254:growth & development; D013379:Substrate Specificity
D000214:Acyl Coenzyme A; D003373:Coumaric Acids; D007527:Isoenzymes; C459096:sinapoyl-coenzyme A; C073734:sinapinic acid; D008031:Lignin; D003066:Coenzyme A Ligases; C019943:4-coumarate-CoA ligase