Amino acid decarboxylase expression

Balan IS, Ugrumov MV, Calas A, Mailly P, Krieger M, Thibault J (2000) Tyrosine Hydroxylase-expressing and/ or aromatic L-amino acid decarboxylase-expressing neurons in the mediobasal hypothalamus of perinatal rats differentiation and sexual dimorphism. J Comp Neurol 25 167-176. 

These strategies are aimed at either cytosolic enzymes, such as L-amino acid decarboxylase, 3-lyase and N-acetyl transferase, or enzymes that are expressed at the brush border of the proximal tubule and to a lesser extent on the basolateral membrane, such as y-glutamyl transpeptidase (GGT). 

The general scheme of the biosynthesis of catecholamines was first postulated in 1939 (29) and finally confirmed in 1964 (Fig. 2) (30). Although not shown in Figure 2, in some cases the amino acid phenylalanine [63-91-2] can serve as a precursor it is converted in the liver to (-)-tyrosine [60-18-4] by the enzyme phenylalanine hydroxylase. Four enzymes are involved in E formation in the adrenal medulla and certain neurons in the brain tyrosine hydroxylase, dopa decarboxylase (also referred to as L-aromatic amino acid decarboxylase), dopamine-P-hydroxylase, and phenylethanolamine iV-methyltransferase. Neurons that form DA as their transmitter lack the last two of these enzymes, and sympathetic neurons and other neurons in the central nervous system that form NE as a transmitter do not contain phenylethanolamine N-methyl-transferase. The component enzymes and their properties involved in the formation of catecholamines have been purified to homogeneity and their properties examined. The human genes for tyrosine hydroxylase, dopamine- 3-oxidase and dopa decarboxylase, have been cloned (31,32). It is anticipated that further studies on the molecular structure and expression of these enzymes should yield interesting information about their regulation and function. 

Selegiline stimulates gene expression of 1-amino-acid decarboxylase in PC12 cells. Neuronal protection ... 

Shen, Y. et al. (2000). Triple transduction with adeno-associated virus vectors expressing tyrosine hydroxylase, aromatic-L-amino-acid decarboxylase, and GTP cyclohydrolase I for gene therapy of Parkinson s disease. Hum. Gene Ther. 11(11), 1509-1519. 

Dopamine is synthesized from the amino acid tyrosine by the enzymes tyrosine hydroxylase (TH which forms L-3,4-dihydroxylphenylalanine, l-DOPA) and L-amino acid decarboxylase (AADC) in dopaminergic neurons. The mRNA expression of the TH (which is the rate-limiting enzyme in the synthesis of dopamine) is abundant throughout the human mesencephalon (Fig. 1) TH is a phenotypic marker for all catecholamines, dopamine, noradrenaline and adrenaline. Evidence for the presence of TH has been documented in the mesencephalon from at least 4.5 to 7 weeks of human fetal life... 

Leitao, M.C., Teixeira, H.C., Barreto Crespo, M.T., San Romao, N.V. (2000). Biogenic amine ocurrence in wine. Amino acid decarboxylase and proteolytic activities expression by Oenococcus oeni. J. Agric. Food Chem., 48, 2780-2784. 

Baker H. 1990. Unilateral, neonatal olfactory deprivation alters tyrosine hydroxylase expression but not aromatic amino acid decarboxylase or GABA immunoreactivity. Neuroscience 36 761-771. 

Azzouz, M., Martin-rendon, E., Barber, R.D., et al. Multicistronic Lentiviral Vector-Mediated Striatal Gene Transfer of Aromatic L -Amino Acid Decarboxylase, Tyrosine Hydroxylase, and GTP Cyclohydrolase I Induces Sustained Transgene Expression, Dopamine Production, and Functional Improvement in a Rat M. J. Neurosci. 22, 10302-10312 (2002)... 

Plant aromatic L-amino acid decarboxylases (AADCs) catalyze the initial reactions in the formation of terpenoid indole alkaloids (TIAs) such as quinine and strychnine, and benzyliso-quiuoline alkaloids (BIAs) such as morphine and codeine (Fig. 3). L-tryptophan decarboxylase (TDC) initiates TIA synthesis with the formation of tryptamine. TDC is encoded by two genes in Cola accuminata TDCl is expressed as part of a developmentally regulated chemical defense system, whereas TDC2 is induced after elicitation with yeast extract or methyl jas-monate (MI). 

Fears have been expressed [510, 511] that long-term administration of L-dopa may induce a state of pyridoxine deficiency, since excess dietary pyridoxine, which is rapidly converted in vivo to the decarboxylase coenzyme pyridoxine-5 -phosphate [512], can nullify the beneficial effects of the amino acid [513-515]. Pyridoxine apparently both complexes with L-dopa and produces an accelerated decarboxylation of the amino acid in extracerebral tissues, both processes effectively reducing the amount of available dopamine in the striatum [512, 516]. The decarboxylase inhibitor MK-485 (37) prevents this reversal of the therapeutic effect by pyridoxine [517] and, more significantly, pyridoxine actually enhances the effects of L-dopa when given in conjunction with such an inhibitor [518]. The mechanism involved in this potentiation reflects enhancement by pyridoxine of dopa decarboxylase activity within the striatum in the presence of complete inhibition of extracerebral decarboxylase. The use of combinations of L-dopa, pyridoxine, and inhibitors of aromatic L-amino-acid decarboxylase, may lead to a more... 

The majority of catecholamine and serotonin biosynthesis occurs within the nerve terminals by synthetic enzymes transported from the neuronal cell bodies. In all catecholamine neurons, the rate-limiting step in synthesis is conversion of tyrosine to dihydroxyphenylalanine by tyrosine hydroxylase. Dihydroxyphenylalanine is then converted to DA, norepinephrine, and epinephrine through a sequential process involving L-aromatic amino acid decarboxylase (conversion of dihydroxyphenylalanine to DA), dopamine-P-hydroxylase (conversion of DA to norepinephrine), and phenylethanol-amine-N-methyltransferase (conversion of norepinephrine to epinephrine). Cell-specific expression of these enzymes determines the main neurotransmitter for an individual catecholamine neuron. The synthesis pathway for serotonin involves a two-step process in which tryptophan hydroxylase first converts tryptophan to 5-hydroxytryptophan, which is then converted to... 

The benzylisoquinolines are formed from two molecules of fhe aromafic amino acid, tyrosine. In the past ten years, this pathway has been probed at the enzyme and gene level. The recent linking of the phloem-specific expression of tyrosine/Dopa decarboxylase (TYDC) genes with the bios)mthesis of the isoquinoline alkaloids in the opium poppy, Papaver somniferum (Facchini and De Luca, 1994, 1995, 2008 Liscombe and Facchini, 2008), and the association with alkaloid accumulation as part of the plant defence mechanism (Wink, 1993 Facchini et al, 1996) are of particular interest in furthering our knowledge of the location of alkaloid biosynthesis. 

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