Diaminobutanoic acid

We might think that the Murchison meteorite would have been studied thoroughly enough in the years since its arrival on Earth. But the results obtained always depend on the performance of the technical resources available in this case, the analytical methods and the apparatus. Thus, it is not really surprising that a new class of amino acid has been discovered in Murchison material diamino acids, such as DL-2,3-diaminopropionic acid, DL-2,4-diaminobutanoic acid etc. These were identified using a new enantioselective GLPC/MS method, which is also being used in analysis of material from the Rosetta mission. 

Although the pK of the cy-amine group for Lys is within the titratable range and that for Arg would probably become so on coordination, the relatively long methylene chains render any tridentate chelation unlikely, and this appears to be the case.10- 4 The shorter methylene side chains in the synthetic diamine-monocarboxylates ornithine, 2,4-diaminobutanoic acid and 2,3-diamino-propionic acid lead to increased tridentate behaviour in that order. 

No structure is assigned a peptide name unless it contains at least two standard amino acid residues. A standard amino acid residue is any amino acid that can stand alone as a stereoparent (e.g., glycine or tryptophan), plus asparagine and glutamine. 2-Aminobutanoic acid and 2,4-diaminobutanoic acid are now considered nonstandard amino acids. 

The copper(II) complex method has been used for the selective N -derivatization of lysine and ornithine as well as of 2,4-diaminobutanoic acid, but not of 2,3-diaminopropanoic acid where the preference for complexation of the a- versus co-amino group is questionable. The additional N -protection of the N -protected anoino acid is then performed according to standard procedures under Schotten-Baumann conditions. 

A new cyclic heptapeptide cupolamide A (55) was isolated from two samples of the sponge Theonella cupola collected in Indonesia and Okinawa [49]. Three of the aminoacid residues, fram,-4-hydroxyproline, homoarginine and 2,4-diaminobutanoic acid are of uncommon occurrence in particular the hydroxy-proline is a constituent of collagen and occasionally has been found in terrestrial biota [50] and in marine... 

Diaminobutanoic acid methyl ester, L Ornithine methyl ester, L Lysine methyl ester, L... 

The lower homologue of lysine and ornithine, 2,4-diaminobutanoic acid, interferes (like the arginine analogue) with reactions of the ornithine cycle, thereby increasing the ammonia content in the blood and brain. 2,3-Diaminopropanoic acid acts as an analogue of glutamate in the nervous system. 

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