I decarboxylases

In the aligned primary structures of class I decarboxylases, the conserved amino acid residues are scattered over their primary structures. There have been few reports to identify the amino acid residues essential for catalytic activity or substrate binding. Huang et al. reported the E-X-P motif in the alignment analysis for 4-hydroxybenzoate decarboxylase of C. hydroxybenzoicum and its homologous unidentified proteins. The E-X-P motif is also conserved in pyrrole-2-carboxylate decarboxylase and indole-3-carboxylate decarboxylase (unpublished data). However, the corresponding motif sequence is not observed in the primary structures of 3,4-dihydroxybenzoate decarboxylase of E. cloacae P241.  

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Decarboxylase activity in //mol COzIm oI tissue-N/60 min. t Decarboxylase activity in jug serotonin produced/g tissue/60 min. i Decarboxylase activity in fig histamine produced/g tissue/180 min. 

The orotic aciduria that accompanies Reye s syndrome probably is a consequence of the inabifity of severely damaged mitochondria to utifize carbamoyl phosphate, which then becomes available for cytosofic overproduction of orotic acid. Type I orotic aciduria reflects a deficiency of both orotate phosphoribosyltransferase and orotidylate decarboxylase (reactions 5 and 6, Figure 34—7) the rarer type II orotic aciduria is due to a deficiency only of orotidylate decarboxylase (reaction 6, Figure 34-7). 

Class I 4-Hydroxybenzoate Chyd 57 3-Octaprenyl-4-hydroxybenzoate decarboxylase... 

Species of Pseudomonas can utilize the a,(i)-diamines putrescine, spermidine, and spermine as sources of carbon and nitrogen, and putrescine can be produced from the secondary amine spermidine together with 1,3-diaminopropane (Dasu et al. 2006). Putrescine (1,4-diaminobutane) is an intermediate in the arginine decarboxylase (ADC) pathway of L-arginine degradation, which is described later, and can be degraded, by two pathways ... 

Besides, potentiometric sensors with ion-selective ionophores in modified poly(vinyl chloride) (PVC) have been used to detect analytes from human serum [128], Cellular respiration and acidification due to the activity of the cells has been measured with CMOS ISFETS [129], Some potentiometric methods employ gas-sensing electrodes for NH3 (for deaminase reactions) and C02 (for decarboxylase reactions). Ion-selective electrodes have also been used to quantitate penicillin, since the penicillinase reaction may be mediated with I or GST. 

Histamine synthesis in the brain is controlled by the availability of L-histidine and the activity of histidine decarboxylase. Although histamine is present in plasma, it does not penetrate the blood-brain barrier, such that histamine concentrations in the brain must be maintained by synthesis. With a value of 0.1 mmol/1 for L-histidine under physiological conditions, HDC is not saturated by histidine concentrations in the brain, an observation that explains the effectiveness of large systemic doses of this amino acid in raising the concentrations of histamine in the brain. The essential amino acid L-histidine is transported into the brain by a saturable, energy-dependent mechanism [5]. Subcellular fractionation studies show HDC to be localized in cytoplasmic fractions of isolated nerve terminals, i.e. synaptosomes. 

Mitra A, Richards I, Kitchin K, et al. 1990. Mirex induces ornithine decarboxylase in female rat liver. J Biochem Toxicol 5(2) 119-124. 

Pyruvate carboxylase is a mitochondrial enzyme and like other carboxylase or decarboxylase enzymes requires biotin as coenzyme. The biotin is firmly attached to the enzyme protein (i.e. a prosthetic group) via a lysine residue. The role of biotin is to hold the C02 in the correct orientation to allow its incorporation into the pyruvate. 

Pyruvate dehydrogenase is a MEC consisting of three separate catalytic proteins (i) a component with combined pyruvate decarboxylase/dehydrogenase activity (ii) a dihydrolipoyl transacetylase (also called acetyl transferase) unit and (iii) linked dihy-drolipoyl dehydrogenase. This is clearly a very big protein the pyruvate decarboxylase/... 

Murakami, Y., Matsueuji, S., Hayashi, S. I., Tanahashi, N., and Tanaka, K. ATP-Dependent inactivation and sequestration of ornithine decarboxylase by the 26 S proteasome are prerequisites for degradation. Mol Cell Biol 1999, 39, 7216-27. 

Figure 2. General topological feature of PS translocation and decarboxylation in mammalian cells. PS is synthesized by PSS I and II in endoplasmic reticulum (ER) or mitochondria-associated membrane (MAM). The nascent PS is transported other membranes such as plasma membrane, nucleus, and mitochondria. The PS transported to the mitochondrial outer membrane is then translocated to the inner membrane, in which PS is converted to PE by PS decarboxylase (PSD). The PE formed in mitochondria is dynamic and can be exported to other organelles for membrane biogenesis.

Rodriquez-Jerez, J., Mora-Ventura, M.T., Lopez-Sabater, E.I. and Hemandez-Herrero, M. (1994). Histidine, lysine, and ornithine decarboxylase bacteria in Spanish salted semipreserved anchovies, J. Food Prot., 57, 784. 

This enzyme [EC 4.1.1.33], also known as mevalonate pyrophosphate decarboxylase, catalyzes the reaction of ATP with (i )-5-diphosphomevalonate to produce ADP, orthophosphate, carbon dioxide, and isopentenyl diphosphate. 

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