Dipeptides, definition

Synonyms 3-Amino-N-(a-carboxyphenethyl) succinamic acid N-methyl ester APM Aspartylphenylalanine methyl ester N-l-a-Aspartyl-l-phenylalanine l-methyl ester Methyl aspartylphenylalanate 1 -Methyl N-L-a-aspartyl-L-phenylalanine Classification Dipeptide Definition Consists of L-aspartic acid and the methyl ester of L-phenylalanine artificial sweetener... 

By any sort of definition, turns are an important feature of protein structure. Kuntz (1972) found 45% of protein backbone in turns or loops Chou and Fasman (1977) found 32% of protein chain in turns (counting four residues per turn) and Zimmerman and Scheraga (1977b) found 24% of the nonhelical residues in turns (counting only the central dipeptide). There are also some particular proteins whose structure appears heavily dependent on turns Fig. 38 shows high-potential iron protein (Carter et ah, 1974), with the 17 turns in 85 residues indicated and their location at the surface evident. 

In the course of investigations of aspartyl dipeptide esters, we had to draw their chemical structures in a unified formula. In an attempt to find a convenient method for predicting the sweettasting property of new peptides and, in particular, to elucidate more definite structure-taste relationships for aspartyl dipeptide esters, we previously applied the Fischer projection technique in drawing sweet molecules in a unified formula 04). 

The propensity of NCAs to polymerize has substantially limited their routine use for sequential peptide synthesis. Upon first reports on the reaction of NCAs with amines or amino acid esters,Baileyt provided a definitive study of the reaction of amino acid esters with a variety of NCAs at —65 °C to give A-carbamoyl dipeptides which on warming to room temperature liberated carbon dioxide to give the free amino dipeptide. The mixture is then recooled to —65°C and condensed with a second NCA to give the tripeptide (Scheme 11). 

Fig. 10.30 Structure of alanine dipeptide showing the definition of the torsions. Reproduced from [76] with permission from Adenine Press.

Definition Dipeptide made of two amin acids, L-aspartic acid and D-alanine Empiricai C14H2SN3O4S 2.5 H2O Properties Wh., crystalline powd., odorless or si. characteristic odor freely sol. in water and ethanol approxi. 2000 times sweeter than sucrose Uses Sweetener for foods Manuf./Distrib. Adept Sol ns. Advanced Ingreds. http //www.advancedingredients.com Danisco Cultor http //ingredients.danisco.conr, TasteTech Ltd http //www.tastech.co.uk Trade Name Synonyms Adame [Danisco Sweeteners... 

Analysis of the solution conformation of the peptides to be described requires the prior definition of the metal binding site. This has been previously reported [6] when it was found for a series of amino acids and dipeptides that the disposition of the headgroup... 

Tsogoeva and coworkers reported the use of oligopeptides of 4-tram-aminopro-hne (tetra- and dipeptides 3 and 4, respectively) as organic catalysts for the Michael reaction of nitroalkanes to cyclic enones. The reaction, in the presence of the achiral additive trans-2,5-dimethylpiperazine, afforded the conjugate addition product in excellent yield and ee up to 88% (Scheme 5.2) [14]. Other dipeptides, with a primary amine at the N-terminus and containing a histidine derivative, were definitely less selective [15] (under the same reaction conditions), while L-proline alone afforded the same product in 93% ee [16]. 

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