《植物生理学报》 2010, 46(4): 359-364
通信作者：王勇；E-mail: wangyong@nankai.edu.cn；Tel: 022-23504 382
摘 要：
利用模式单细胞植物莱茵衣藻, 研究不同培养条件下细胞中丝氨酸: 乙醛酸氨基转移酶活性的变化情况。结果表明: 莱茵衣藻 SGAT 酶活性的最适 pH 介于 5~7 之间, 当 pH 高于 7 以后, 酶活性逐渐下降; 随着细胞密度增加, SGAT 酶活性降 低; 光强可显著影响SGAT酶活性, 在一定光强范围内, 随着光照强度的增加, 酶活性增强; 乙酸作为莱茵衣藻的唯一异养碳 源也会影响SGAT酶活性, 两者间呈正相关; 提高氧浓度, 显著地提高了细胞内SGAT的酶活性; 当二氧化碳浓度增加时, 细 胞内 SGAT 的酶活性也略有升高; 40 ℃高温和 15 ℃低温处理后, SGAT 酶活性均降低。此外, 提高氧浓度时细胞内 Gly 含 量增加, Ser 含量减少, Gly/Ser 的比值从 0.79 提高到 1.49。关键词：SGAT; 细胞密度; 光照强度; 乙酸; 氧浓度; 光呼吸; 莱茵衣藻
收稿：2010-01-19 修定：2010-03-28
资助：国家自然科学基金(30870185)。
Corresponding author: WANG Yong; E-mail: wangyong@nankai.edu.cn; Tel: 022-23504 382
Abstract:
In this study, the model single cell plant Chlamydomonas reinhardtii was used to investigate variations in serine: glyoxylate aminotransferase activity in cells under different cultural conditions. The results showed the optimum pH of SGAT was in the range of 5–7, and SGAT decreased gradually when the pH was higher than 7. SGAT activity in the cell also declined with the increase of cell density. SGAT activity was influenced significantly by the light intensity, and the effect strengthened with the increase of light intensity. Moreover, acetate, which was the sole carbon source of C. reinhardtii in heterotrophic growth, also affected the SGAT activity. In addition, SGAT activity in the cell increased remarkably when the oxygen concentration was higher than that in the normal air, and the increased carbon dioxide concentration treatment also led to an increase. The SGAT activity both reduced under 40 or 15 ℃. Furthermore, the content of Gly was increased and the content of Ser was decreased when the oxygen pressure increased in the air, resulting in a raise in Gly/Ser ratio from 0.79 to 1.49.Key words: SGAT; cell density; light intensity; acetate; oxygen pressure; photorespiration; Chlamydomonas reinhardtii
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