Voo K S, Whetten R W, O'Malley D M, Sederoff R R
Department of Forestry, North Carolina State University, Raleigh 27695-8008, USA.
Plant Physiol. 1995 May;108(1):85-97. doi: 10.1104/pp.108.1.85.
4-Coumarate:CoA ligase (4CL, EC 6.2.1.12) was purified from differentiating xylem of loblolly pine (Pinus taeda L.). The pine enzyme had an apparent molecular mass of 64 kD and was similar in size and kinetic properties to 4CL isolated from Norway spruce. The pine enzyme used 4-coumaric acid, caffeic acid, ferulic acid, and cinnamic acid as substrates but had no detectable activity using sinapic acid. 4CL was inhibited by naringenin and coniferin, products of phenylpropanoid metabolism. Although the lignin composition in compression wood is higher in p-hydroxyphenyl units than lignin from normal wood, there was no evidence for a different form of 4CL enzyme in differentiating xylem that was forming compression wood. cDNA clones for 4CL were obtained from a xylem expression library. The cDNA sequences matched pine xylem 4CL protein sequences and showed 60 to 66% DNA sequence identity with 4CL sequences from herbaceous angiosperms. There were two classes of cDNA obtained from pine xylem, and the genetic analysis showed that they were products of a single gene.
4-香豆酸：辅酶A连接酶（4CL，EC 6.2.1.12）是从火炬松（Pinus taeda L.）正在分化的木质部中纯化得到的。该松树酶的表观分子量为64 kD，在大小和动力学性质上与从挪威云杉中分离得到的4CL相似。该松树酶以4-香豆酸、咖啡酸、阿魏酸和肉桂酸作为底物，但对芥子酸没有可检测到的活性。4CL受到苯丙烷类代谢产物柚皮素和松柏苷的抑制。尽管受压木中的木质素组成在对羟基苯基单元方面比正常木材中的木质素含量更高，但没有证据表明在正在形成受压木的分化木质部中存在不同形式的4CL酶。从木质部表达文库中获得了4CL的cDNA克隆。cDNA序列与松树木质部4CL蛋白序列匹配，并且与草本被子植物的4CL序列显示出60%至66%的DNA序列同一性。从松树木质部获得了两类cDNA，遗传分析表明它们是单个基因的产物。
