TCA cycle


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cycle

 [si´k'l]
a succession or recurring series of events.
cardiac cycle a complete cardiac movement, or heart beat, including systole, diastole, and the intervening pause.
Cardiac cycle. From Applegate, 2000.
cell cycle the cycle of biochemical and morphological events occurring in a reproducing cell population; it consists of the S phase, occurring toward the end of interphase, in which DNA is synthesized; the G2 phase, a relatively quiescent period; the M phase, consisting of the four phases of mitosis; and the G1 phase of interphase, which lasts until the S phase of the next cycle.
citric acid cycle tricarboxylic acid cycle.
estrous cycle the recurring periods of estrus in adult females of most mammalian species and the correlated changes in the reproductive tract from one period to another.
hair cycle the successive phases of the production and then loss of hair, consisting of anagen, catagen, and telogen.
menstrual cycle see menstrual cycle.
ovarian cycle the sequence of physiologic changes in the ovary involved in ovulation; see also ovulation and reproduction.
reproductive cycle the cycle of physiologic changes in the reproductive organs, from the time of fertilization of the ovum through gestation and childbirth; see also reproduction.
sex cycle (sexual cycle)
1. the physiologic changes that recur regularly in the reproductive organs of nonpregnant female mammals.
2. the period of sexual reproduction in an organism that also reproduces asexually.
tricarboxylic acid cycle the cyclic metabolic mechanism by which the complete oxidation of the acetyl portion of acetyl-coenzyme A is effected; the process is the chief source of mammalian energy, during which carbon chains of sugars, fatty acids, and amino acids are metabolized to yield carbon dioxide, water, and high-energy phosphate bonds. Called also citric acid cycle, Krebs cycle, and TCA cycle.
 Central pathways of metabolism: How the body produces energy from the energy-containing nutrients using the tricarboxylic acid cycle. From Davis and Sherer, 1994.
urea cycle a cyclic series of reactions that produce urea; it is a major route for removal of the ammonia produced in the metabolism of amino acids in the liver and kidney.

TCA cycle

Abbreviation for tricarboxylic acid cycle.

TCA cycle (Tricarboxylic Acid Cycle)

see KREBS CYCLE.
References in periodicals archive ?
Because of the high prevalence of IDH1/2 mutations in cancers compared with other TCA cycle aberrations, the most widely studied oncometabolite is D-2-hydroxyglutarate.
In metabolites analysis, [alpha]-ketoglutaric acid and fumaric acid were filtered (before exercise and/or after exercise) which associated with not only TCA cycle metabolism but also alanine, aspartate, and glutamate metabolism.
However, hippocampal slices of db/db mice exhibited hampered metabolism of glutamate and glutamine, observed as decreased [sup.13]C labeling of several key amino acids and TCA cycle intermediates.
Firstly, fatty acid [beta]-oxidation, the main energy source of heart, was inhibited during MI, then amino acids could be readily metabolized into TCA cycle intermediates and become an important fuel source.
The metabolomic data suggest disruption of the TCA cycle because decreased levels of TCA intermediates were detected in the groups exposed to [As.sup.III] in utero (Table 2).
Mean environmental conditions in the hour prior to sampling (sample sizes are n = 6 at noon, and n = 5 at midnight) Parameter Noon mean [+ or -] SD Aragonite saturation 4.6 [+ or -] 0.3 pH 8.16 [+ or -]0.04 Temperature ([degrees]C) 28.2 [+ or -] 0.3 DO saturation (%) 124 [+ or -] 6 Parameter Midnight mean [+ or -] SD Aragonite saturation 4.0 [+ or -] 0.2 pH 8.08 [+ or -]0.03 Temperature ([degrees]C) 27.6 [+ or -]0.1 DO saturation (%) 93 [+ or -] 3 Differences in the number of components of the fatty acid degradation, TCA cycle, glycolysis, and oxidative phosphorylation pathways with at least a 20% increase in expression at noon or midnight No.
Theoretical coefficient of performance (COP) of the TCA cycle is 0.68, and, according to the manufacturer, the practical COP of the TCA chiller is from 0.52 to 0.58.
This phase also regenerates stores of insulin depleted in the first phase of insulin secretion and is likely stimulated by metabolites such as NADPH and a-ketoglutarate produced by pyruvate cycling pathways involving TCA cycle intermediates such as citrate, malate, and oxaloacetate [29, 37, 44].
However the intake of CRA increases the activities of TCA cycle enzymes probably by improving the mitochondrial antioxidant defense system and overcome the complications associated with the decrease TCA cycle function.
This reaction curtails normal fatty acid oxidation and the TCA cycle. This results in accumulation of acetyl-CoA or fats with net production of ketone bodies.
It has been well documented that citrate, 2-ketoglutarate, malic acid and succinate are the crucial substances of TCA cycle, which is the main pathway of glucose degradation and is primary energy supplier for universal organisms (Ni et al., 2007).