Togasaki R K, Levine R P
J Cell Biol. 1970 Mar;44(3):531-9. doi: 10.1083/jcb.44.3.531.
A mutant strain of the green alga Chlamydomonas reinhardi, ac-20, is described in which both the rate of CO(2) fixation by whole cells and the rate of carboxylation of ribulose-1,5-diphosphate in cell-free extracts are reduced, particularly when sodium acetate is present in the growth medium. Of the enzymes of the reductive pentose phosphate cycle tested, only ribulose-1,5-diphosphate carboxylase activity is reduced in the mutant strain, and it appears that the low carboxylase activity limits the strain's rate of photosynthetic carbon metabolism. Evidence is presented to show that the fluctuation in the level of the enzyme activity in the presence or absence of acetate results from the fluctuation in the level of some factor(s) limiting the rate of synthesis of the protein.
描述了莱茵衣藻的一种突变株ac - 20,其中全细胞固定CO₂的速率以及无细胞提取物中1,5 - 二磷酸核酮糖的羧化速率均降低,尤其是当生长培养基中存在乙酸钠时。在所测试的还原性戊糖磷酸循环的酶中,只有突变株中的1,5 - 二磷酸核酮糖羧化酶活性降低,并且似乎低羧化酶活性限制了该菌株的光合碳代谢速率。有证据表明,在有或没有乙酸盐存在的情况下,酶活性水平的波动是由限制蛋白质合成速率的某些因素水平的波动引起的。