PROTEIN TURNOVER IN WHEAT AND SNAPDRAGON LEAVES: PRELIMINARY INVESTIGATIONS

Publisher Website
Google Scholar
Abstract
Detached primary wheat leaves and attached cotyledons and primary leaves of snapdragons were allowed to photoassimilate C14O2for short periods of time. They were subsequently kept in air and samples were taken at various time intervals and analyzed for protein nitrogen, and amounts and total radioactivities of soluble sugars and amino acids and protein amino acids. A method of estimating protein turnover from these data is discussed. Amounts and specific activities of respired carbon were also determined for wheat leaves.Minimum protein turnover rates of about 0.5 to 1.5% per hour were found in rapidly growing snapdragon leaves and in snapdragon cotyledons. Lower rates were found in detached, non-growing wheat leaves and slowly growing snapdragon leaves. Little contribution could have been made by proteins as substrates for respiration in detached wheat leaves. It is suggested that protein turnover in leaves is mainly associated with growth and biochemical differentiation.