Kinetics and Energetics of Light-driven Chloroplast Glutamine Synthesis.
نویسندگان
چکیده
Chloroplasts contain the enzyme glutamine synthetase. Formation of glutamine by isolated chloroplasts is light-dependent and requires an intact outer envelope. Addition of exogenous glutamic acid, as well as nitrogen donors such as nitrite or ammonium, stimulate the synthesis of this amide. Photosynthetic generation of ATP satisfies the light requirement of glutamine synthesis. The process is supported by cyclic as well as noncyclic photophosphorylation.
منابع مشابه
Photorespiration and light act in concert to regulate the expression of the nuclear gene for chloroplast glutamine synthetase.
In Pisum sativum, distinct chloroplast and cytosolic forms of glutamine synthetase (GS) are encoded by homologous nuclear genes that are differentially expressed in vivo (Tingey, S. V., Tsai, F.-Y., Edwards, J. W., Walker, E. L., and Coruzzi, G. M. [1988]. J. Biol. Chem. 263, 9651-9657). In leaves, light selectively affects the expression of the nuclear gene for chloroplast GS2. Differences in ...
متن کاملEvidence for an operative glutamine translocator in chloroplasts from maritime pine (Pinus pinaster Ait.) cotyledons.
In higher plants, ammonium is assimilated into amino acids through the glutamine synthetase (GS)/glutamate synthase (GOGAT) cycle. This metabolic cycle is distributed in different cellular compartments in conifer seedlings: glutamine synthesis occurs in the cytosol and glutamate synthesis within the chloroplast. A method for preparing intact chloroplasts of pine cotyledons is presented with the...
متن کاملDNA REPLICATION AND SYNTHESIS OF DNABINDING PROTEINS IN THE CHLOROPLASTS OF A CALLUS CULTURE
Continuous labelling of callus with H-thymidine results in intermittent peaks of H-DNA per chloroplast, showing synchrony of division. The increase in H-DNA could be due to several replication rounds, and the drop to successive plastid divisions without intervening DNA synthesis. The level of DNA-binding proteins in the chloroplast parallels the peaks of plastidal DNA synthesis; such pro...
متن کاملSynthesis and Characterization of CdS/g-C3N4/rGO Composite and Evaluation of its Photocatalytic Performance from Kinetics Perspective
In this research, CdS/g-C3N4 /rGO ternary composite was prepared by hydrothermal method and characterized using various techniques including X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM) and UV-Visible spectrophotometer. The photocatalytic activity of the prepared composite was evaluated from kinetics perspective by studying the removal of ciprofloxacin antibioti...
متن کاملChloroplast and cytosolic glutamine synthetase are encoded by homologous nuclear genes which are differentially expressed in vivo.
We have shown that the individual members of the plant gene family for glutamine synthetase (GS) are differentially expressed in vivo, and each encode distinct GS polypeptides which are targeted to different subcellular compartments (chloroplast or cytosol). At the polypeptide level, chloroplast GS (GS2) and cytosolic GS (GS1 and GSn) are distinct and show an organ-specific distribution. We hav...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Plant physiology
دوره 55 1 شماره
صفحات -
تاریخ انتشار 1975