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Aminotransferases reaction

FIGURE 14.26 (a) Antigen used to create an abzyme with aminotransferase activity, (b) Aminotransferase reaction catalyzed by the abzyme. [Pg.458]

The probable metabohc defect in type I tyrosine-mia (tyrosinosis) is at himarylacetoacetate hydrolase (reaction 4, Figure 30-12). Therapy employs a diet low in tyrosine and phenylalanine. Untreated acute and chronic tyrosinosis leads to death from liver failure. Alternate metabolites of tyrosine are also excreted in type II tyrosinemia (Richner-Hanhart syndrome), a defect in tyrosine aminotransferase (reaction 1, Figure 30-12), and in neonatal tyrosinemia, due to lowered y>-hydroxyphenylpyruvate hydroxylase activity (reaction 2, Figure 30-12). Therapy employs a diet low in protein. [Pg.255]

Such intermediates are known to form between substrate and enzyme in the aldolase reaction and between pyri-doxal 5-phosphate and the amino group of enzyme or substrate in aminotransferase reactions. In the latter case, aldimine formation accounts for the high affinity of coenzyme binding to apotransaminases. [Pg.360]

Historically, the amine was an aromatic amine but is now generalized to any amine. A Schiff base, also called an aldimine, is formed in the pyridoxal 5-phosphate-dependent aminotransferase reactions. [Pg.630]

FIGURE 18-4 Enzyme-catalyzed transaminations. In many aminotransferase reactions, a-ketoglutarate is the amino group acceptor. All aminotransferases have pyridoxal phosphate (PLP) as cofactor. Although the reaction is shown here in the direction of transfer of the amino group to a-ketoglutarate, it is readily reversible. [Pg.660]

FIGURE 22-11 Ornithine 6-aminotransferase reaction a step in the mammalian pathway to proline. This enzyme is found in the mitochondrial matrix of most tissues. [Pg.844]

Aminotransferase reaction using a-ketoglutarate as the amino-group acceptor. [Pg.248]

Cyclic interconversion of pyridoxal phosphate and pyridoxamine phosphate during the aspartate aminotransferase reaction. [Pg.249]

Figure 13.21 L-Lysine e-aminotransferase reactions to Omapatrilate precursors (Patel, 2000). Figure 13.21 L-Lysine e-aminotransferase reactions to Omapatrilate precursors (Patel, 2000).
From the sequence of reactions found it follows that copper-quinoprotein amine oxidases catalyze an aminotransferase reaction. A different reaction sequence occurs with flavoprotein amine oxidases (EC 1.4.3.4), where formation of NH3 is not dependent on the presence of 02. However, since reductive trapping of amines in the first half-reaction [86] showed attachment of substrate but not of tritium, the mechanism is also different from the aminotransferase reaction that... [Pg.577]

Amino acids. Glutamate (along with aspartate) is a key substrate and product in transamination (aminotransferase) reactions for amino acid interconversions. Aminotransferases carry out the general reaction ... [Pg.69]

Answer The measurement of the activity of alanine aminotransferase by measurement of the reaction of its product with lactate dehydrogenase is an example of a coupled assay. The product of the transamination (pyruvate) is rapidly consumed in the subsequent indicator reaction, catalyzed by an excess of lactate dehydrogenase. The dehydrogenase uses the cofactor NADH, the disappearance of which is conveniently measured by observing the rate of decrease in NADH absorption at 340 nm. Thus, the rate of disappearance of NADH is a measure of the rate of the aminotransferase reaction, if NADH and lactate dehydrogenase are added in excess. [Pg.198]

Answer The second amino group introduced into urea is transferred from aspartate. This amino acid is generated in large quantities by transamination between oxaloacetate and glutamate (and many other amino acids), catalyzed by aspartate aminotransferase. Approximately one half of all the amino groups excreted as urea must pass through the aspartate aminotransferase reaction, and liver contains higher levels of this aminotransferase than of any other. [Pg.200]

Oxoglutarate is the normal acceptor of the amino group. In the aminotransferase reaction, 2-oxoglutarate is transaminated to give glutamate. There are at least 13 different aminotransferases, but their specificities are not all known. The most important are (a) aspartate aminotransferase, which catalyzes the following reversible reaction ... [Pg.422]

Pyruvic acid is an important metabolite in its own right as we shall see shordy. It is the simplest a-keto-acid (2-oxopropanoic acid). Having the two carbonyl groups adjacent makes them more reactive the ketone is more electrophilic and enolizes more readily and the acid is stronger. Pyruvate is in equilibrium with the amino acid alanine by an aminotransferase reaction catalysed by pyridoxal (above). [Pg.1390]

The next step in building a biochemical network model for the TCA cycle is determining the governing differential equations. Since we are not treating transport of material into or out of the mitochondrion, the reactants of the overall reaction of Equation (6.31) are held clamped in this model. In addition, ASP and GLU are held fixed because there are no sources or sinks for the metabolites other than the aspartate aminotransferase reaction built into the model at this stage. Since the electron transport system is not modeled, proton transport is not included and pH is held fixed. [Pg.152]

Studies performed by the authors of this review [142,144], suggest that the discrepancies are due to functional microcompartmentation between the aspartate aminotransferase and the aspartate transporter. The apparent for aspartate efflux can be dramatically decreased by generation of intramitochondrial aspartate by the aminotransferase reaction. Detailed isotopic studies using labelled matrix aspartate in liver mitochondrial [142] and labelled intramitochondrial glutamate in kidney mitochondria [144] confirmed the initial suggestion. [Pg.237]

FIGURE 7 Detailed mechanism of aminotransferase reaction- All of the steps ate reversible. Double arrows arc shown oi ly at fiteps 3 and 8 to emphasize the importance of the refsonance that stabilizes the carbanion, that is, allows a ncgallve charge to diwclop on the a-carbon of the substrate. [Pg.544]

When a linked enzyme assay, known as an indicator reaction, is used to determine the activity of a different enzyme, it is essential that the primary reaction be the rate-limiting step. For example, in the determination of aspartate aminotransferase activity, the indicator reaction is the reduction of the oxaloacetate formed in the aminotransferase reaction to malate by malate dehydrogenase and NADH. The activity of the indicator enzyme must be sufficient to ensure the virtually instantaneous removal of the product of the first reaction, to prevent significant reversal of the first reaction. The measured enzyme is typically acting under conditions of saturation with respect to its substrate however, the concentration of the substrate of the indicator enzyme (i.e., the... [Pg.202]

Erecinska M, Nelson D, Nissim I, Daikhin Y, Yudkoff M (1994) Cerebral alanine transport and alanine aminotransferase reaction — alanine as a source of neuronal glutamate. J Neurochem 62 1953-1964. [Pg.228]

Pyridoxal phosphate The coenzyme that is required for transaminase (aminotransferase) reactions, as weU as other enzymes. It is the active form of pyridoxine (vitamin B ). [Pg.357]

Figure 17-12. Enzymatic production of D-alanine by combination of aspartase, aspartate racemase, and D-amino acid aminotransferase reactions. Figure 17-12. Enzymatic production of D-alanine by combination of aspartase, aspartate racemase, and D-amino acid aminotransferase reactions.

See other pages where Aminotransferases reaction is mentioned: [Pg.457]    [Pg.651]    [Pg.270]    [Pg.238]    [Pg.231]    [Pg.268]    [Pg.842]    [Pg.398]    [Pg.398]    [Pg.25]    [Pg.140]    [Pg.81]    [Pg.241]    [Pg.241]    [Pg.225]    [Pg.270]    [Pg.241]    [Pg.606]    [Pg.40]    [Pg.46]    [Pg.270]    [Pg.889]    [Pg.1288]    [Pg.292]   
See also in sourсe #XX -- [ Pg.414 , Pg.418 ]




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Aminotransferases

Aminotransferases half reactions

Aminotransferases methyltransferase reactions

Transamination of Amino Acids (Aminotransferase Reactions)

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