Abstract
A large-scale culture system for Chlorella vulgaris has been established and growth conditions determined for optimal production of nitrate reductase. Nitrate reductase was purified from collected cells. A novel method for the determination of the temperature dependence of enzymic reactions was used to determine the activation energy for the NADH-dependent nitrate reductase activity and NADH-dependent cytochrome c reductase activity of the nitrate reductase from Chlorella vulgaris. In addition to the native enzyme, three variant forms of the enzyme were prepared. The steady-state turnover numbers for the four forms were determined. Kinetics of the reduction of the heme of the enzyme were monitored by stopped flow spectrophotometry. On the basis of comparisons between the steady-state and transient-state kinetics of the reactions, a new model for the electron pathway in the nitrate reductase from Chlorella vulgaris is proposed. This model suggests a parallel rather than serial transfer of electrons from FAD to nitrate.
Mahan, James Rudolp (1984). Flow of electrons in nitrate reductase from Chlorella vulgaris. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -435677.