Institute of Radiation Biology, College of Nuclear Sciences, National Tsing Hua University, Hsin Chu 30043, Taiwan, Republic of China.
Plant Physiol. 1987 Sep;85(1):158-63. doi: 10.1104/pp.85.1.158.
Radiation inactivation technique was employed to determine the functional size of photosynthetic electron transport chain of spinach chloroplasts. The functional size for photosystem I+II (H(2)O to methylviologen) was 623 +/- 37 kilodaltons; for photosystem II (H(2)O to dimethylquinone/ferricyanide), 174 +/- 11 kilodaltons; and for photosystem I (reduced diaminodurene to methylviologen), 190 +/- 11 kilodaltons. The difference between 364 +/- 22 (the sum of 174 +/- 11 and 190 +/- 11) kilodaltons and 623 +/- 37 kilodaltons is partially explained to be due to the presence of two molecules of cytochrome b(6)/f complex of 280 kilodaltons. The molecular mass for other partial reactions of photosynthetic electron flow, also measured by radiation inactivation, is reported. The molecular mass obtained by this technique is compared with that determined by other conventional biochemical methods. A working hypothesis for the composition, stoichiometry, and organization of polypeptides for photosynthetic electron transport chain is proposed.
辐射失活技术被用来测定菠菜叶绿体光合电子传递链的功能大小。结果表明，光系统 I+II（H2O 到甲基紫精）的功能大小为 623±37 千道尔顿；光系统 II（H2O 到二甲基喹啉/铁氰化物）为 174±11 千道尔顿；光系统 I（还原二氨基二脲到甲基紫精）为 190±11 千道尔顿。364±22（174±11 和 190±11 的总和）千道尔顿和 623±37 千道尔顿之间的差异部分可以解释为存在两个 280 千道尔顿的细胞色素 b(6)/f 复合物分子。本文还报道了通过辐射失活测定的其他光合电子流部分反应的分子量。本文用该技术得到的分子量与其他传统生化方法的测定结果进行了比较。提出了光合电子传递链的组成、化学计量和多肽组织的工作假设。
