Regulation of Glutamine Synthetase by Light and during Nitrogen Deficiency in Synchronous Chlorella sorokiniana

Publisher Website
Google Scholar
Abstract
A method is described to achieve density labeling of proteins in unicellular algae by using 13CO2. This is a satisfactory procedure especially for work on N2 metabolism. The increase in activity of glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.7.1) in C. sorokiniana mediated by a dark/light shift and by N2 starvation were investigated. Using the method of density labeling and isopycnic centrifugation, the increase in enzyme activity was demonstrated after a dark/light shift is based on activation rather than de novo synthesis. The increase in enzyme activity after transfer to N2-deficient medium is based both on activation and de novo synthesis.