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Amino acid sequences deamination

The D-enantiomer of 393 was obtained in an identical sequence of reactions starting frc m 2,3-0-isopropylidene-4-deoxy-D-threitol (395). This compound was prepared from L-threonine (394) in the following way the amino acid was deaminated to 25 3/ -dihydroxy-butyric acid. Esterification of the carboxyl group and protection of both hydroxyl groups with an isopropylidene grouping gave methyl 4-deoxy-2,3-0-isopropylidene-D-threonate. Reduction of the ester group afforded 395 smoothly. [Pg.203]

The amino acid sequence of the F. soiam DAO (11) shows 37% identity to that of T. variabilis DAO (12) and 25% identity to that of porcine kidney DAO [EC 1-4-3.3] (13,14), which has a weak oxidative activity against cephalosporin C (Figure 2). The amino acid sequence of T. variabiUs DAO also shows relatively low identity (20%) to that of porcine kidney DAO. The T. variofctlis and F. soiani DAOs have the same approximate oxidative deamination rate against cephalosporin C, in spite of the amino acid sequence identity being relatively low. [Pg.736]

Subsequently, the TriA enzyme, which catalyzes hydrolytic deamination of the aminated s-triazine melamine, was found to be 98% identical to AtzA (46,47). While only 9 amino acids out of 475 differed, TriA had insignificant activity with atrazine as a substrate. AtzA shows no activity with aminoatrazine. Thus, TriA and AtzA had conqiletely distinct enzymatic functions despite an amino acid sequence identity of 98%. [Pg.44]

The RNA molecule of one of the most thoroughly studied viruses, tobacco mosaic virus (TMV), has the structure of a single-stranded polynucleotide consisting of approximately 6000 nucleotides. The fact that this RNA contains the information determining amino acid sequence in the protein of the virus coat (158 amino acid residues in each protein molecule) is shown not only by the widely known and extensive data on infectivity of pure tobacco mosaic virus RNA and its ability to reproduce whole virus, but also, in a more direct form, by investigations of inherited changes in the amino acid sequence of this protein as a result of experimental modifications of flie nucleotide composition of the virus RNA by the action of nitric acid and other substances under carefully controlled conditions. Such treatment causes deamination... [Pg.26]

There is an important biochemical counterpart of the deamination reaction that utilizes pyridoxal phosphate, 7, as the aldehyde. Each step in the sequence is catalyzed by a specific enzyme. The a-amino group of the amino acid combines with 7 and is converted to a keto acid. The resulting pyridoxamine then reacts to form an imine with a different a-keto acid, resulting in formation of a new a-amino acid and regenerating 7. The overall process is shown in Equation 25-6 and is called transamination. It is a key part of the process whereby amino acids are metabolized. [Pg.1224]

The success of the Wolff-Kishner and related C==0 to CH2 transformations (see Chapter 1.14, this volume) attests to the efficiency of the diazene decomposition route applied to the reductive deamination of primary amines, this requires methods which transform RNH2 into RN=NH, which corresponds to an amination-oxidation sequence. Several one- or two-step processes have been described which carry out this transformation. Treatment of amino acids in alkaline solution with excess hydroxylamine-O-sul-fonic acid (HOS) gave moderate yields of deamination product, as exemplified by the dipeptide case shown in equation (23). [Pg.828]

Oxidation. The oxidation of amino acids is probably the principal nonbiological decomposition reaction under aerobic conditions. Except for some preliminary studies, however, there have been few investigations of this reaction. The reaction is likely an oxidative deamination, producing ammonia and the a-keto acid of the corresponding amino acid. The a-keto acid may decarboxylate to give an aldehyde. The over-all reaction sequence can be written as... [Pg.320]

In RNA editing the nucleotide sequence of a pre-mRNA is altered in the nucleus. In vertebrates, this process is fairly rare and entails deamination of a single base in the mRNA sequence, resulting in a change in the amino acid specified by the corresponding codon and production of a functionally different protein (see Figure 12-17). [Pg.509]

Finally, the important principle of subtractive analysis should be mentioned. Selective decomposition of the N-terminal residue is possible, for instance by deamination with nitrous acid or through oxidative deamination with ninhy-drin. Quantitative amino acid analysis before and after the reaction will show the absence of one amino acid in the hydrolysate of the treated sample. Obviously this is the residue with the free amino group hence it must have occupied the N-terminal position in the sequence. [Pg.19]

The chemical reactions for the conversion of homoserine to a-ketobutyric acid in the vertebrate organism, if that is the pathway, are quite obscure. In Neurospora homoserine is the precursor of threonine (see the chapter, Synthetic Processes Involving Amino Acids, which in turn is deaminated to a-ketobutyric acid (see Fig. 3, reaction 4). The reaction sequence from homoserine to threonine probably is through/3-y-dihydroxy-a-aminobutyric acid as an intermediate. [Pg.75]

Adenosine deaminase converts adenosine monophosphate back to inosine monophosphate, liberating ammonia. This sequence of reactions thus provides a pathway for the deamination of a variety of amino acids, linked to transamination, similar to those shown in Figure 9.9 for transamination linked to glutamate dehydrogenase or glycine oxidase. [Pg.273]

Protoadamantanone has been prepared by the nitrous acid deamination of 2-amino-l-adamantanol (77%), by aprotic diazo-tization of endo-7-aminomethylbicyclo[3.3.1]nonan-3-one in benzene with an equivalent amount of acetic acid (67%), and by thermolysis of 1-adamantyl hypohalites followed by base-promoted cyclization of the resulting halo ketones (32-37%)." In spite of low and erratic yields, the last reaction sequence has provided the most convenient route to the protoadamantanes, since the other two approaches require lengthy syntheses of the starting materials. [Pg.76]

Walden inversion on C2 has occurred in one of these sequences if in the first, then chitose, chitonic acid and isosaccharic acid have the configuration of D-mannose if in the second, i. e., in the deamination of 2-amino-D-gluconic acid, then chitaric acid and epi-isosaccharic acid are... [Pg.78]

In all known instances, the deamination of 2-amino-2-deoxyaldo-hexonic acids by nitrous acid takes place with formation of a 2,5-anhydro ring and with retention of the configuration at C-2, as illustrated in the sequence 21—>22—>23. [Pg.191]


See other pages where Amino acid sequences deamination is mentioned: [Pg.237]    [Pg.1476]    [Pg.568]    [Pg.1574]    [Pg.607]    [Pg.842]    [Pg.38]    [Pg.113]    [Pg.504]    [Pg.563]    [Pg.542]    [Pg.42]    [Pg.724]    [Pg.468]    [Pg.231]    [Pg.190]    [Pg.75]    [Pg.356]    [Pg.1386]    [Pg.1223]    [Pg.305]    [Pg.308]    [Pg.124]    [Pg.61]    [Pg.278]    [Pg.513]    [Pg.452]    [Pg.38]    [Pg.205]    [Pg.91]    [Pg.253]    [Pg.893]    [Pg.315]    [Pg.411]    [Pg.18]    [Pg.50]   


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