do Nascimento J R, Cordenunsi B R, Lajolo F M, Alcocer M J
Departamento de Alimentos e Nutrição Experimental, FCF Universidade de São Paulo, Brazil.
Planta. 1997;203(3):283-8. doi: 10.1007/s004250050193.
A 952-base pair polymerase-chain-reaction product of sucrose-phosphate synthase (SPS) (EC 2.3.1.14) from banana (Musa acuminata cv. Nanicão) fruit was cloned and used to study expression of the enzyme during development and ripening. The deduced amino acid sequence shows that banana SPS has a high homology with the leaf, tap-root and bean enzymes from other species. Enzyme activity, and mRNA and protein levels point to an increase in SPS expression during ripening. The accumulation of sucrose was correlated to starch degradation and happened 4 d after SPS mRNA and activity had reached their maxima. These results indicate that access to substrate and transcriptional activation with increase in SPS expression might be important regulatory events of sweetening during banana fruit ripening.
从香蕉（Musa acuminata cv. Nanicão）果实中克隆得到了蔗糖磷酸合酶（SPS）（EC 2.3.1.14）的一段952个碱基对的聚合酶链反应产物，并用于研究该酶在果实发育和成熟过程中的表达情况。推导的氨基酸序列表明，香蕉SPS与其他物种的叶片、主根和豆类中的该酶具有高度同源性。酶活性、mRNA和蛋白质水平表明，SPS在成熟过程中的表达增加。蔗糖的积累与淀粉降解相关，且在SPS mRNA和活性达到最大值4天后发生。这些结果表明，底物的可利用性以及随着SPS表达增加的转录激活可能是香蕉果实成熟过程中甜度增加的重要调控事件。
