Absence of a common intermediate pool among individual enzyme chains of the energy-conservation pathway in chloroplasts of Euglena gracilis
Year: 1970
Type: article
Abstract: Tri-n-butyltin chloride is a specific inhibitor that binds stoicheiometrically and irreversibly with the ATP-synthesizing sites of chloroplasts. Titration of Euglena chloroplasts with tri-n-butyltin chloride shows about six ATP-synthesizing sites per molecule of cytochrome c(552) or per 380 molecules of chlorophyll. This system was used to study the possibility of linkage between individual enzyme chains of the energy-conservation pathway or the possible existence of a common pool of an intermediate in this pathway. The inhibition of ATP synthesis by tri-n-butyltin chloride at low rates of electron transport (low light-intensities, NADP(+) or ferricyanide as electron acceptor) agrees with a kinetic model of two to four ATP-synthesizing sites per energy-conservation chain. At high rates of electron transport, however, the results occasionally agree with a model of 20 or more sites per chain. The results are interpreted as indicating the absence of a common intermediate pool, but the presence of a limited degree of linkage between individual chains. It also indicates the presence of two energy-conservation sites in these chloroplasts.
Source: Biochemical Journal
DOI: 10.1042/bj1160055
Author: Joseph S. Kahn
Institution: North Carolina State University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: bronze
Funder: North Carolina State University
OpenAlex ID: W89770159
