【摘要】 水稻幼苗经低温(0℃)处理后,叶片中PEP羧化酶活性明显地降低.Km值增大。经1—2天低温处理者,增加反应底物的浓度,有减少PEP羧化酶活性降低的幅度;当低温伤害严重时(0℃4天),这种效应则消失。这些结果表明:水稻叶片中PEP羧化酶对低温反应是敏感的,其活性的下降是由于该酶对底物的亲和力的降低。更多还原

【Abstract】 After chilling treatment(0℃),the decrease of PEP-carboxylase activity in rice leaves was obvious with the increased Km value.The postponement of the dip in PEP-carboxylase activity followed by the lift in the substrate concentration after 1-2 days chilling treatment,but no postponement after 4 days chilling treatment were found.These results showed that PEP-carboxylase in rice leaves was sensitive to chilling due to the decrease in affinity of the enzyme to the substrate.After chilling treatment(0℃),the decrease of PEP-carboxylase activity in rice leaves was obvious with the increased Km value.The postponement of the dip in PEP-carboxylase activity followed by the lift in the substrate concentration after 1-2 days chilling treatment,but no postponement after 4 days chilling treatment were found.These results showed that PEP-carboxylase in rice leaves was sensitive to chilling due to the decrease in affinity of the enzyme to the substrate.更多还原