Analysis of dipeptides

P. Gillespie, J. Cicariello, G.L. Olson, Conformational analysis of dipeptide mimetics. Biopolymers 43 (1997) 191-217. 

Amino Acid/Pimer Analysis. The analysis of dipeptides and the covalent attachment of peptides to carbohydrate was monitored by a high performance liquid chromatographic method (33). 

Gibson G, El-Agnaf OM, Anwar Z, Sidera C, Isbister A, Austen BM (2005) Stmcture and neurotoxicity of novel amyloids derived from the BRI gene. Biochem Soc Trans 33 1111-1112 Gillespie P, Cicariello J, Olson GL (1997) Conformational analysis of dipeptide mimetics. Biopolymers 43 191-217... 

TBDMS derivatives have also been applied to the analysis of dipeptides [75]. 

Figure 22 An example of sensing array for the analysis of dipeptides, which was described by Severin, by employing different metallic complexes of know dyes.

Ivanova, B.B. 2005. Solid state linear-dichroic infrared spectral analysis of dipeptide L-Phe-L-Phe and its mononuclear Au(III)-complex. J. Coord. Chem. 58 587-593. 

Koleva, B.B., T.M. Kolev, and St. Todorov. 2007. Structural and spectroscopic analysis of dipeptide methionyl-glycine and its hydrochloride. Chem. Papers 61 490-496. 

Cheam, T. C. 1993. Normal Mode Analysis of Alanine Dipeptide in the Crystal Conformation Using a Scaled Ab Initio Force Field. J. Mol. Struct. 295,259-271. 

Schafer, L., C. Van Alsenoy, and J. N. Scarsdale. 1982. Ab Initio Studies of Structural Features Not Easily Amenable to Experiment. 23. Molecular Structures and Conformational Analysis of the Dipeptide N-acetyl-N -methyl Glycyl Amide and the Significance of Local Geometries for Peptide Structures. J. Chem. Phys. 76, 1439-1444. 

By quenching the aminolysis reaction at various times and examining the diastereomer ratios in the unreacted Co(III)-ester and Co(III)-dipeptide products it has been possible to build up complete concentration-stereochemistry-time profiles for several couplings. One such example is given in Fig. 7, and kinetic analysis of these data allows the rate constants for epimerization (ku k2) and aminolysis (k3, ki) to be found. Some results obtained in this way are listed in Table X. 

The sections presented above provide an account of the separate topics into which translation can be divided. These act as an introduction to the current section, in which a description of the individual reactions in peptide synthesis is presented in a single diagram, i.e. a diagram that encapsulates the whole process (Figure 20.22). An analysis of each separate reaction provides a simple explanation of the interactions that are required in a sequential manner to form the various complexes in the pathway, the activities of which result in the synthesis of, initially, a dipeptide but then a growing peptide. The repetition of the formation of the complexes for each amino acid results in the synthesis of the final peptide, as dictated by the base sequence in the mRNA. 

Slomczynska, U., Chalmers, D.K., CORNILLE, F., Smythe, M.L., Beusen, D.D., Moeller, K.D., Marshall, G.R. Electrochemical cyclization of dipeptides to form novel bicyclic, reverse-turn peptidomimetics. 2. Synthesis and conformational analysis of 6,5-bicyclic systems./. Org. Chem. 1996, 63(4), 1198-1204. 

Figure 2.11 LC analysis of cystine DCL. Trace A shows the DCL templated with CaM, and trace B shows the blank DCL. The amplified peaks ( ) are dipeptides ce and cc. Reproduced from Reference 23 with permission of Wiley-VCH Verlag GmbH Co. KGaA. Copyright Wiley-VCH Verlag GmbH Co. KGaA.

The classical methods for detection and quantitation of racemization require analysis of the chiral purity of the product of a peptide-bond-forming reaction. For example, the Anderson test is used to explore a variety of reaction conditions for the coupling of Z-Gly-Phe-OH to H-Gly-OEt (Scheme 6). 9 The two possible enantiomeric tripeptides are separable by fractional crystallization, so that gravimetric analysis furnishes the racemization data. This procedure has a detection limit of 1-2% of the epimerized tripeptide. A modification by Kemp,1"1 utilizing 14C-labeled carboxy components, extends the detection limit by two to three orders of magnitude by an isotopic dilution procedure. The Young test 11 addresses the coupling of Bz-Leu-OH to H-Gly-OEt, and the extent of epimerization is determined by measurement of the specific rotation of the dipeptide product. 

Sensory analysis of mixed solutions of MSG and each of four dipeptides was carried out (Table VI). The umami taste of MSG was not changed when it was mixed with peptides containing aspartic acid. On the other hand, Glu-Glu, produced the... 

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