Transamination products

In the authors opinion (81UK1252), the evidence for such a scheme is the isolation of formamide transamination products, dialkylformamides (in case of l-dialkylaminoalk-l-en-3-ynes). Examples of formamide transamination, e.g., by /3-amino-substituted carbonyl compounds, are known [58CB2832 60CB1402 60HC( 14)272],... 

Hydrolysis of the a-keto acid imine by nucleophilic addition of water to the C=M bond gives the transamination products pyridoxamine phosphate (PMP) and a-keto acid. 

The wild type ilvA gene was modified to target the protein to the plastid and expressed in A. thaliana. Transgenic plants showed a 20-fold increase in levels of 2-ketobutyrate as well as a large increase in 2-aminobutyrate, the transaminated product of 2-ketobutyrate [27, 41]. The levels of threonine remained stable whereas isoleucine concentration increased. Constitutive expression of the ilvA protein along with bktB, phaA, and phaC proteins in the plastids of A. thaliana led to the synthesis of poly(3HB-co-3HV) in the range of 0.2 - 0.8 % dry weight, with a HV level between 4-17 mol % [27,41]. Co-expression of the iso-... 

The result is that the amino groups can be dumped out as alanine (the transamination product of pyruvate). In the liver and kidney, alanine is transaminated to yield pyruvate and glutamate. As in the Cord cycle, the pyruvate is converted to glucose by the liver and is shipped out. The glutamate is fed into the urea cycle-nitrogen disposal system to get rid of the excess nitrogen. 

The transamination product of sarcosine nitrite and P(NMe2)3 rearranges to a cyclic aminophosphine (104) which on thermolysis (120°C/20 mbar) yields the diazaphosphole (105) <86PS(28)71). Condensation of a 1,2-diiminoethane (R = cyclohexyl) with PCI3 yields a 2,4-dichlorodihydro-l,3,2-diazaphosphole (106) <88DOK(298)369> which is converted to the 1,3,2-diazaphospholium ion (107)... 

Muscle activity involves processes such as aerobic and anaerobic glycolysis and is therefore accompanied by an increased pyruvate production. Consequently, the pyruvate transamination product alanine will be increased after exercise. Heavy exercise may be associated with an increased need of creatine biosynthesis from arginine. Ornithine is a by-product of this pathway and may be increased under these conditions. 

At pH 7.5 less than 1% of the compound exists in the open-chain a-keto-acid form while at pH 9 approximately 3% is in a form that reacts as a typical a-keto acid. Glutamine transaminase also catalyzes the transamination of glutamic acid y-A -methylamide the expected transamination product, a-keto-A-methylglutaramic acid has not yet been isolated from a transamination reaction mixture. However, this compound was... 

Amino acid Transamination product Decarboxylation product Notes... 

Transamination Products of the Amino Acids Vitamin Be-Responsive Inborn Errors of Metabolism Indices of Vitamin Be Nutritional Status Reference Intakes of Vitamin Be Adverse Effects of Hyperhomocysteinemia Indices of Folate and Vitamin B12 Nutritional Status Reference Intakes of Folate Reference Intakes of Vitamin B12... 

Copolymeric polysilazanes can also be prepared. The transamination products of Tris and vinyl-Tris with methylamine, which have already been described, can be cocondensed to form a new copolymeric composition ... 

The ceramic products of these pyrolyses were completely amorphous. Pyrolysis carried out at 1500 °C or lower yields only amorphous products. Amorphous materials can be converted to crystalline form by heating above the transition temperature. Pyrolysis must be carried out at 1550 °C or higher to obtain crystalline products. Thus, pyrolysis of the transamination product of Tris with ammonia at 1550 °C or higher gave high-purity, a-phase silicon nitride (33), as analyzed by powder X-ray difiraction (Figure 1 and Table I). 

Figure 1. Representative X-ray powder diffraction spectrum of [Si(NH2)2]> which is the product of pyrolysis at 1550 °C of the transamination product of Tris with ammonia, a and P refer to a- and -phase silicon nitride, respectively.

In maple syrup urine disease, the enzyme complex that decarboxy-lates the transamination products of the branched-chain amino acids is defective (see Figure 7-11). Valine, isoleucine, and leucine accumulate. Urine has the odor of maple syrup. Mental retardation occurs. 

Reactions subsequent to transamination have been reported, one being the diconjugate formation shown In equation 2. Spontaneous cyclization of a pyruvate Intermediate was proposed as the mechanism for formation of the N,N-dlsubstltuted hemlamlnal (equation 6) found as a metabolite of benzyllsothlocyanate (31). Another common biotransformation for transamination products Is sulfoxidation. 

Sulfoxidation. Sulfoxidation Is common in sulfur biochemistry (43,44), and has been observed with many of the transamination products listed in Table III, with mercapturic acids (45,46,47) and cysteine conjugates (12). Sulfoxidation is also common with the methylthio-containing metabolites produced from cysteine conjugates (see "Thiol Formation" below). Sulfoxidation increases the polarity of compounds and therefore affects their excretability. 

Color determination of the reaction core from the humidity series show an increase in color formation with increasing humidity, however, to a reduced extent compared to 1-amino propan-2-one production (Figure 7). As might be expected the formation of the transamination product of 2-oxopropanal originating from glucose breakdown and die recombination with the amino acid only partially represents those potentially similar chemical reactions which are responsible for color formation. 

There was different reactivity shown if the C-7 position was unsubstituted. Thus, reaction of 165 with ammonia gave the addition/oxidation product 166, whereas, with methylamine, only the transamination product 167 was obtained (Scheme 13) <2003HCA139>. 

Reticuline.—A biosynthetic study of the important benzylisoquinoline reticuline (41), published in preliminary form/ has appeared in full/ Important new information is that 4-hydroxyphenylpyruvic acid (37) and 3,4-dihydroxyphenyl-pyruvic acid (38) are incorporated, like tyrosine, into both C6-C2 units of recticuline (41), in contrast to the transamination product of (38), i.e. dopa (39), which, curiously, is only used for the elaboration of one of these units (ring A and attached ethanamine residue), being incorporated via dopamine (40). Condensation of dopamine with (38) affords (43), which has been shown to be a benzylisoquinoline precursor followed in sequence by (42). The new results confirm these findings by showing that (42) and (43) are reticuline precursors too. 

The hypothesis that branched amino acids are metabolized to branched fatty acids via a-keto acid intermediates is further supported by incubations with deuterated 2-oxo-3-methylpentanoate and 2-oxo-4-methylpentanoate/ the transamination products of lie and Leu respectively. GC/MS of acyl groups resulting from incubation with d2 -2-oxo-4-methylpentanoate (deuterated at C-3) revealed deuterium incorporation into glucose esters containing d2-3-methylbutyrate and d2-9-methyldecanoate. Trace amounts of d2-7-methyloctanoate were also observed, supporting the hypothesis that branched chain precursors are elongated by the addition of acetate. 

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