what is the rate limiting enzyme of kreb's cycle
Isocitrate dehydrogenase
title: Sodium fluoroacetate text: has a pivotal role in cellular metabolism. Fluoroacetate disrupts the citric acid cycle (also known as the Krebs cycle) by combining with coenzyme A to form fluoroacetyl CoA, which reacts with citrate synthase to produce fluorocitrate which binds very tightly to aconitase, thereby halting the citric acid cycle. This inhibition results in an accumulation of citrate in the blood. Citrate and fluorocitrate are allosteric inhibitors of phosphofructokinase-1 (PFK-1), a key enzyme in glycolysis. When PFK-1 is inhibited, cells are no longer able to metabolize carbohydrates, depriving them of energy. In humans, the symptoms of poisoning normally appear between 30 minutes title: Diffusion limited enzyme text: Diffusion limited enzyme A Diffusion limited enzyme is an enzyme which catalyses a reaction so efficiently that the rate limiting step is that of substrate diffusion into the active site, or product diffusion out. This is also known as kinetic perfection or catalytic perfection. Since the rate of catalysis of such enzymes is set by the diffusion-controlled reaction, it therefore represents an intrinsic, physical constraint on evolution (a maximum peak height in the fitness landscape). Diffusion limited perfect enzymes are very rare. Most enzymes catalyse their reactions to a rate that is 1,000-10,000 times slower than this limit. This is title: Basal metabolic rate text: an intake of oxygen along with coenzymes to provide energy for survival (usually from macronutrients like carbohydrates, fats, and proteins) and expel carbon dioxide, due to processing by the Krebs cycle. For the BMR, most of the energy is consumed in maintaining fluid levels in tissues through osmoregulation, and only about one-tenth is consumed for mechanical work, such as digestion, heartbeat, and breathing. What enables the Krebs cycle to perform metabolic changes to fats, carbohydrates, and proteins is energy, which can be defined as the ability or capacity to do work. The breakdown of large molecules into smaller molecules—associated with title: Biological aspects of fluorine text: real rat surviving while cooled and immersed in perfluorocarbon. (See also list of fictional treatments of perfluorocarbon breathing.) An estimated 30% of agrichemical compounds contain fluorine. Most of them are used as poisons, but a few stimulate growth instead. Sodium fluoroacetate has been used as an insecticide, but it is especially effective against mammalian pests. The name "1080" refers to the catalogue number of the poison, which became its brand name. Fluoroacetate is similar to acetate, which has a pivotal role in the Krebs cycle (a key part of cell metabolism). Fluoroacetate halts the cycle and causes cells to be title: Enzyme text: "turnover number", which is the number of substrate molecules handled by one active site per second. The efficiency of an enzyme can be expressed in terms of "k"/"K". This is also called the specificity constant and incorporates the rate constants for all steps in the reaction up to and including the first irreversible step. Because the specificity constant reflects both affinity and catalytic ability, it is useful for comparing different enzymes against each other, or the same enzyme with different substrates. The theoretical maximum for the specificity constant is called the diffusion limit and is about 10 to 10 (M