Aminooxy acetate

The use of oxime bond formation with orthogonal protection techniques allows the efficient construction of an antiparallel four-helix-bundle TASP122 (Scheme 19) by condensing amphiphilic peptide blocks, containing aldehyde functions at the C- or N-terminus, to a topological template functionalized with selectively addressable aminooxy acetic acid moieties, t20,22,971... 

L-/D-cvsteine. Hydrogen sulfide is produced from L-cysteine in a light-independent process that can be inhibited in vivo and in vitro by aminooxy acetic acid, an inhibitor of pyridoxal phosphate-dependent enzymes the hydrogen sulfide emitted in response to L-cysteine is directly derived from die L-cysteine fed ( 2 ). Therefore, hydrogen sulfide appears to be produced from L-cysteine by a pyridoxal phosphate-dependent, L-cysteine specific cysteine desulfhydrase. This conclusion is supported by the finding that in cucurbit... 

CARBOXYMETHOXYLAMINE HEMIHYDROCHLORIDE (Acetic acid, aminooxy-, hydrochloride)... 

Dissolve 10 mM 0-(carboxymethyl)hydroxylamine (sold as (aminooxy)acetic acid or carboxymethoxyl amine) and 4 mM keto-hapten in a mixture of 200 ml ethanol... 

The inhibition data for the aminooxy acids was treated similarly (Table I). For the series of aminooxy acids ranging from the acetate to the valerate, and for gabaculine, there was little change in kcat (range from 0.11 to 0.18 sec ) whereas there was a 210-fold range of values of K[Pg.130]

Inhibition by the aminooxy acids increased as the carbon chain lengthened from 1 to 4 (acetate to the butyrate) but then decreased as the length increased to 5 with the valerate. This is perhaps to be expected since the butyrate most closely resembles GABA, the substrate. 

Figure 4 Absorbance spectrum for pyridoxal phosphate, alone and 1n the presence of aminooxy acetate(l), propionate(2), butyrate(3) and valerate(4).

The intramolecular cyclocondensation of 1-(2-hydroxylaminoethyl) cytosine (90) gave pyrim-ido[2,l-c][l,2,4]oxadiazines (91) and (92) (Scheme 8) <71JCS(C)867>. The attempted esterification of aminooxy acetic acid intermediate (94) led by ring closure to (18) (Scheme 9) <70H(22)1879>. Some of the biologically active pyrimido[2,3-Z ][l,3,5]thiadiazines (9 were obtained from pyrimido-2-thiones (96) and A -aryl-AT-chloromethylcarbamoylchlorides (95) (Equation (18)) <83FRP2512450). 

Alanine appears to be formed primarily by alanine dehydrogenase in A. cylindrica, C. licheniformey P. boryanumy and A. nidulanSy because the inhibition of formation of glutamate and glutamine by methionine sulfoximine is not accompanied by a comparable inhibition in the formation of alanine (Table I). Moreover, alanine formation by these species was not reduced in the presence of aminooxy acetate, an inhibitor of amino transfer reactions (I3,J4). However, in A. variabilis alanine appears to be formed by a transamination reaction, because synthesis of [ N]alanine from was strongly inhibited in the presence of... 

Two observations indicate that aspartate is formed primarily by a transamination reaction, probably from glutamate, rather than by a direct amination with NH4 in A. cylindrica. First, N-label in aspartate was reduced more than 90% by the presence of aminooxy acetate, while labeling of glutamate and glutamine was not reduced (IS). Second, [ N]aspartate was not detected when glutamate formation was inhibited either directly, by azaserine, or indirectly, when glutamine s)mthesis was inhibited by methionine sulfoximine (13). Moreover, activity of a glutamate-aspartate aminotransferase reaction has been detected in vitro in two strains of A. cylindrica (1,26). 

The sequential labeling of first citrulline and then arginine are consistent with the idea that citrulline is a substrate for the synthesis of arginine. In cyanobacteria, citrulline appears to be formed by the condensation of carbamyl phosphate with ornithine (27). The inhibition of formation of citrulline (and arginine) by methionine sulfoximine, azaserine, and aminooxy acetate could be due to the reduced formations of ornithine from glutamate and carbamyl phosphate from glutamine. In... 

Fig. 1. The structures of a-aminooxy acetic acid(AOA) and a-aminooxy-B-phenyl-propionic acid (AOPP)...

Related Reagents. S-(4-Methylbenzyl)-2-(aminooxy)ethane-thiol This auxiliary, which is easily removed following ligation by N-0 bond cleavage with Zn in acetic acid, suffers from a slower cyclization step due the six-membered transition state. 

When we were developing an assay for the estimation of PAL activity in intact cells,we employed a-aminooxy-acetate (AOA) as a transaminase inhibitor. When it became clear that AOA was a weak inhibitor of buckwheat PAL (K = 120 we rationalized that the aminooxy analog of... 

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