title: An improved equation and assay for determining the CO(2)/O(2) specificity for Rubisco.
abstract: The determination of the CO(2)/O(2) specificity factor (Omega) is very important to investigate the Rubisco carbon assimilation efficiency. In this paper, it is proved that previous formulae can introduce notable errors into calculating the CO(2)/O(2) specificity factor (Omega) because CO(2) and O(2) are both the substrates and the mutually competitive inhibitors for Rubisco. A simple integrated equation is proposed to calculate the CO(2)/O(2) specificity factor (Omega). On the other hand, previous multi-step procedures, including the manipulation of radioisotope ((14)C and/or (3)H) and the chromatographic separation of the products, are inconvenient and may cause much random error. An improved assay procedure is presented therefore, which includes the spectrophotometric measurement of 3-phosphoglycerate-dependent NADH oxidation with a coupled enzyme system.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, 100084, P. R, China, dbsznm@mail.tsinghua.edu.cn.
authors.forename: Guofu
authors.initials: G
authors.lastname: Li
authors.forename: Haibin
authors.initials: H
authors.lastname: Mao
authors.forename: Xiang
authors.initials: X
authors.lastname: Ruan
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xu
authors.forename: Yandao
authors.initials: Y
authors.lastname: Gong
authors.forename: Xiufang
authors.initials: X
authors.lastname: Zhang
authors.forename: Nanming
authors.initials: N
authors.lastname: Zhao