番木瓜芥子酶基因的表达调控和酶活性研究

以番木瓜为材料，通过RT-PCR方法，研究了芥子酶基因CpTGG1和CpTGG2在不同组织器官的表达情况，结果表明CpTGG1基因在番木瓜的茎、叶、花、种子中表达，在根和果实中不表达，而CpTGG2仅在根中表达，在其它器官中都没有检测到表达产物，表明两个芥子酶基因存在明确的分工。两个基因都不在果肉中表达。酶活性测定表明，除了果肉外的其它器官中都有芥子酶活性，这与RT-PCR的结果是一致的。对叶片芥子酶的活性研究结果表明，其最适pH8．0，最适温度为45℃，高温下（80℃）酶迅速失活，最适Vc浓度为1．5mM，高盐浓度对酶活性有抑制作用。

Expression and enzymatic analysis of myrosinases in Carica papaya

Differential expression of myrosinase genes CpTGG1 and CpTGG2 in different organs of Carica papa-ya was investigated by RT-PCR, The results indicated that CpTGG1 was expressed in stem, leaf, flower and seed, not expressed in root and fruit, while CpTGG2 was only expressed in root, and no expression was found in other organs, which indicated that two myrosinase genes have functional allocation. Myrosinase activity was de-tected in all the tested organs except for pulp, which is consistent with the result of RT-PCR. Myrosinase isolat-ed from leaf tissue had an optimal reaction pH of 8.0, an optimal temperature of 45℃, and optimal Vc concen-tration of 1.5 mM. Papaya myrosinase was inactivated by high temperature and inhibited by high concentration of salt, which is different characteristic compared to other reported myrosinases.