Aspartic acid, acetyl derivative

Selectivity studies with DTU indicated marked discrimination in the clathrate formation 23,45). As in other types of clathrates, the steric factor is important in differentiation between compounds of similar functionality but different shape. For example, DTU forms crystalline complexes with some alcohols (methanol, ethanol, propanol, 1-butanol) but not with others (2-butanol). It complexes the ethyl esters of N-acetyl derivatives of glycine, alanine, methionine and aspartic acid, but not of proline, serine, phenylalanine and glutamic acid. 

Reactions 3 and 4 indicate that with aspartic acid, aspartic transcarbamylase, and carbamyl-P or acetyl-P, either carbamyl aspartate or acetyl aspartate can be formed. Carbamyl aspartate is the first intermediate in the formation of pyrimidines, and acetyl aspartate, of unknown function, is the amino acid derivative present in the largest concentration in brain of most species (43). 

Two D-aminoacylases have been described that resemble the L-specific acylase II from kidney, which only hydrolyzes the N-acyl derivatives of L-aspartic acid. The d-specific counterpart of acylase II, N-acetyl-D-aspartate deacetylase, has been isolated from Alcaligenes xylosoxydans subsp. xylosoxydans,n The same strain produces an aminoacylase which specifically hydrolyzes N-acyl derivatives of D-glutamic acid131L The latter N-acetyl-D-glutamate deacetylase has also been found in Pseudomonas sp. 33. ... 

Although several proposals and studies of the biosynthesis of vasicine (8) have been made, the complete biosynthetic route is not known with certainty, [carboxy Anthranilic acid is incorporated into vascicine in Adha-toda vasica with incorporation of the carboxyl label (Johne, 1986). It is established that anthranilic acid, probably as the A -acetyl derivative, also is incorporated. The acetyl portion accounts for the origin of C-3 and C-10. Aspartic acid may explain the origin of the remaining portion of the molecule (Johne, 1986) (Fig. 31.4). 

At the organ level, lithium has been associated with an increase in cortical grey matter as examined using structural magnetic resonance imaging (MRI) [25 ] and an increase in N-acetyl-aspartate, a derivative of aspartic acid, which is a marker of neuronal health, measured by magnetic resonance spectroscopy [26 j. These neuroprotective characteristics of lithium may reduce the risk of dementia. 

The cycle was originally proposed as a mechanism for the terminal oxidation of carbohydrate. It was always obvious that it must also apply to parts of the protein molecule because several amino acids yield members of the cycle directly—glutamic acid, aspartic acid, and alanine—or indirectly—histidine, proline, arginine, and others. Work carried out during the last decade with the help of specially prepared tissue extracts and of isotopes has produced conclusive evidence in support of the conception that the tricarboxylic acid cycle is also the terminal mechanism of the oxidation of fatty acids and ketone bodies. These substances all form the same derivative of acetic acid—acetyl coenzyme A— which can condense with oxalacetate to form citrate. The pathway leading from various... 

By boiling for a short time in dilute acetic acid specific splitting of the molecule occurred after a residue of aspartic acid. N-Acylaspartic acid was isolated as well as a hexapeptide (36), the structure of which was established by mass spectrometry of the acetylated, permethylated or perdeuteriomethylated derivatives. 

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