The isocitrate dehydrogenase phosphorylation cycle. Identification of the primary rate-limiting step.
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چکیده
منابع مشابه
Phosphorylation inactivates Escherichia coli isocitrate dehydrogenase by preventing isocitrate binding.
Equilibrium binding studies demonstrate that purified Escherichia coli isocitrate dehydrogenase binds isocitrate, alpha-ketoglutarate, NADP, and NADPH at 1:1 ratios of substrate to enzyme monomer. The phosphorylated enzyme, which is completely inactive, is unable to bind isocitrate but retains the ability to bind NADP and NADPH. Replacement of serine 113, which is the site of phosphorylation, b...
متن کاملThe phosphorylation of isocitrate dehydrogenase in Escherichia coli.
The regulation of enzyme activity by reversible covalent phosphorylation has been reviewed by Krebs & Beavo (1979). Although this mechanism of modulating the catalytic activity of enzymes is well known in many eukaryotic systems, it has been reported only recently in bacteria. At this time, NADP:isocitrate dehydrogenase (EC 1.1.1.42) is the only one of several phosphorylated bacterial proteins ...
متن کاملConformational changes represent the rate-limiting step in the transport cycle of maize sucrose transporter1.
Proton-driven Suc transporters allow phloem cells of higher plants to accumulate Suc to more than 1 M, which is up to ~1000-fold higher than in the surrounding extracellular space. The carrier protein can accomplish this task only because proton and Suc transport are tightly coupled. This study provides insights into this coupling by resolving the first step in the transport cycle of the Suc tr...
متن کاملAMPylation targets the rate-limiting step of BiP’s ATPase cycle for its functional inactivation
The endoplasmic reticulum (ER)-localized Hsp70 chaperone BiP contributes to protein folding homeostasis by engaging unfolded client proteins in a process that is tightly coupled to ATP binding and hydrolysis. The inverse correlation between BiP AMPylation and the burden of unfolded ER proteins suggests a post-translational mechanism for adjusting BiP's activity to changing levels of ER stress, ...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1988
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)77658-3