Carboxylase activity

Mayoral, M.L., Atsmon, D., Gromet-Elhanan, Z. Shimshi, D. (1981). Effect of water stress on enzyme activities in wheat and related wild species Carboxylase activity, electron transport and photophosphorylation in isolated chloroplasts. Australian Jourrml of Plant Physiology, 8, 385-94. 

Insulin stimulates lipogenesis by several other mechanisms as well as by increasing acetyl-CoA carboxylase activity. It increases the transport of glucose into the cell (eg, in adipose tissue), increasing the availability of both pyruvate for fatty acid synthesis and glycerol 3-phosphate for esterification of the newly formed fatty acids, and also converts the inactive form of pyruvate dehydrogenase to the active form in adipose tissue but not in liver. Insulin also—by its ability to depress the level of intracellular cAMP—inhibits lipolysis in adipose tissue and thereby reduces the concentration of... 

Yu, A., Drejer, J., Hertz, L. etal. Pyruvate carboxylase activity in primary cultures of astrocytes and neurons. /. Neurochem. 41 1484-1487,1983. 

Knafo, L., Chessex, P., Rouleau,T., and Lavoie, J-C. (2005), Association between hydrogen peroxide-dependent byproducts of ascorbic acid and increased hepatic acetyl-CoA carboxylase activity, Clin. Chem., 51,1462-1471. 

Additional information <1> (<1> two other cAMP-independent kinases found, that phosphorylate but do not effect acetyl-CoA carboxylase kinase activity [6] <1> phosphorylation by cAMP-dependent protein kinase has the same effect on acetyl-CoA carboxylase activity then phosphorylation with acetyl-CoA carboxylase kinase-2 [6,7] <1> cAMP-dependent protein kinase identified, that phosphorylates and inactivates acetyl-CoA carboxylase in vitro, but appears not to be involved in regulation in vivo [8]) [6-8]... 

Ottey, K.A. Munday, M.R. Calvert, D.T. Clegg, R.A. Effect of anoxia on acetyl-CoA carboxylase activity possible role for an AMP-activated protein kinase. Biochem. Soc. Trans., 17, 350-351 (1989)... 

Willmer, C.M. (1983). Phosphoeno/pyruvate carboxylase activity and stomatal operation. Physiologie Vegetale 21, 943-53. 

Another unique property of at least some of the halobacteria is the ability to grow phototrophically by employing the light-driven proton pump bacteriorhodopsin. The proton gradient that is produced is used directly to generate ATP (Hartmann et al., 1980 Oesterhelt and Kripphal, 1983). Photoassimilation of CO2 by halobacteria was shown by Danon and Caplan (1977) and Oren (1983). In vivo C02 fixation was demonstrated by Javor (1988) and the existence of the enzyme ribulose-bisphosphate carboxylase activity in several halobacteria was shown by Altekar and Rajagopalan (1990). 

Dubost, G. and Gendraud, M., Phosphoenolpyruvate carboxylase activity of dormant or nondormant Jerusalem artichoke tubers relation with the intracellular pH, C. R. Acad. Sci. Ill, 305, 619-622, 1987. 

Several enzymes involved in the biosynthesis of phenethylamines in plants have been studied. A tyrosine carboxy-lyase (decarboxylase) isolated from barley seedlings and barley roots has been studied in considerable detail (347-349). The enzyme is rather specific for L-tyrosine and meta-tyrosine ort/io-tyrosine and L-dopa are decarboxylated slowly. Tyrosine carboxylase activity was also demonstrated in wheat and maize (348). Cytisus scoparius contains dopa car-boxy-lyase which decarboxylates d- and L-dopa at about the same rate (350). Tyrosine is decarboxylated 15 times slower. A similar enzyme has been found in the alga Monostroma juscum (174). 

Both multiple carboxylase deficiencies are characterized by deficient activities of the three mitochondrial carboxylases in peripheral blood leukocytes prior to biotin treatment. The carboxylase activities increase to near normal or normal after treatment with pharmacological doses of biotin. Patients with biotin holocarboxylase synthetase deficiency have deficient activities of the three mitochondrial carboxylases in fibroblasts incubated in medium with low biotin concentrations (containing only the biotin contributed by fetal calf serum added to the medium for cell growth), whereas patients with biotinidase deficiency have normal carboxylase activities under these conditions. The activities of the carboxylases in biotin holocarboxylase synthetase deficiency become near normal to normal when cultured in medium supplemented with high concentrations of biotin. 

The mainstay of therapy in biotinidase deficiency is biotin supplementation. To date, all symptomatic children with biotinidase deficiency have improved after treatment with 5 to 10 mg of biotin per day. Biotin appears to be required in the free form as opposed to the bound form. This is based on the findings of two children who were fed yeast as a form of therapy. Neither improved because essentially all of the biotin in yeast is protein bound, and these children could not recycle the biotin. These children, however, did improve when treated with free biotin. Treatment with biotin is essential and sufficient to prevent or resolve the symptoms. It is not necessary to treat children with biotinidase deficiency with protein-restricted diets as it is in some of the isolated carboxylase deficiencies because with biotin therapy all the carboxylase activities are normal. Symptoms of biotinidase deficiency are preventable if patients are diagnosed and treated at birth or before symptoms occur. 

Figure 4. Effect of haloxyfop methyl ester (A), haloxyfop free acid (O), and tralkoxydim ( ) on acetyl CoA carboxylase activity from maize.

Ngoj of 800 imol mol-1 it approaches to within 10% of the value occurring when the ambient O2 level is reduced 10-fold (about 0.081 mol CCVmol photons). Such raising of the CO2 level is another way of favoring the carboxylase activity of Rubisco. Also, the requirement for a high /V1 for C3 plants is consistent with the Kcoz of about 10 mmol m-3 for CO2 fixation by Rubisco.13... 

Shirra, M.K., Patton-Vogt, J., Ulrich, A., Liuta-Tehlivets, O., Kohlwein, S.D., Henry, S.A., and Arndt, K.M., 2001, Inhibition of acetyl coenzyme A carboxylase activity restores expression of the INOl gene in a snfl mutant strain of Saccharomyces cerevisiae. Mol. Cell. Biol. 21 5710-5722. 

The vitamin K-dependent carboxylase is an integral membrane protein. Most of the proteins that are carboxylated are extracellular proteins, and the major activity of the carboxylase is at the luminal face of the rough endoplasmic reticulum. However, there is also significant carboxylase activity in mitochondria. 

Holocarboxylase synthetase deficiency can be diagnosed prenatally by assessing the response of carboxylase activity in cultured amniocytes (obtained by amniocentesis) to the addition of biotin, or by the detection of methylcitric and hydroxyisovaleric acids in the amniotic fluid. Prenatal therapy, by giving the mother 10 mg of biotin per day, results in sufficiently elevated fetal blood concentrations of biotin to prevent the development of organic acidemia at birth. 

Bannister DW (1976a) The biochemistry of fatty liver and kidney syndrome. Biotin-mediated restoration of hepatic gluconeogenesis in vitro and its relationship to pyruvate carboxylase activity. Biochemical Journal 156, 167-73. 

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