Mizukami H, Nordlöv H, Lee S L, Scott A I
Biochemistry. 1979 Aug 21;18(17):3760-3. doi: 10.1021/bi00584a018.
Strictosidine synthetase, which catalyzes the condensation of tryptamine with secologanin to form strictosidine (isovincoside), was purified 740-fold to homogeneity from cultured cells of Catharanthus roseus in 10% yield. The specific activity is 5.85 nkat/mg. The molecular weight as estimated by gel filtration is 38,000. The isoelectric point is 4.6. Apparent Km values for tryptamine and secologanin are 0.83 and 0.46 mM, respectively. The enzyme shows a broad pH optimum between 5.0 and 7.5. The product of the enzymic reaction is exclusively strictosidine, while no trace of its epimer vincoside can be detected. Sulfhydryl inhibitors have no effect on the enzyme. End products in the biosynthetic pathway of indole alkaloids such as ajmalicine, vindoline, and catharanthine do not inhibit the activity of strictosidine synthetase.
从长春花培养细胞中纯化出了严格苛定碱合成酶，该酶催化色胺与裂环马钱子苷缩合形成严格苛定碱（异长春苷），纯化了740倍达到同质，产率为10%。比活性为5.85纳卡特/毫克。通过凝胶过滤估计的分子量为38,000。等电点为4.6。色胺和裂环马钱子苷的表观米氏常数分别为0.83和0.46毫摩尔。该酶在5.0至7.5之间表现出较宽的最适pH值。酶促反应的产物仅为严格苛定碱，未检测到其差向异构体长春苷的痕迹。巯基抑制剂对该酶无作用。吲哚生物碱生物合成途径中的终产物如阿吗碱、文多灵和长春质碱不抑制严格苛定碱合成酶的活性。
