HYDROXYLAMINE METABOLISM IN MONORAPHIDIUM BRAUNII

Abstract

SUMMARYThe utilization of nitrate by cells of Monoraphidium braunii Legnerova was immediately impaired by low concentrations of hydroxylamine. The consumption of NO3-resumed when almost no hydroxylamine was left in the culture medium but resumption took place only under illumination with blue ligbt. Tbe addition of bydroxylamine to cell suspensions caused tbe rapid mactivation of nitrate reductase. Tbe inactivation was largely prevented by tbe previous incubation of tbe cells witb menadione, a finding wbicb suggests tbat bydroxylamine inactivates tbe reduced form of nitrate reductase. Illumination of cells previously treated witb bydroxylamine promoted tbe in situ reactivation of tbe enzyme.