V-Terminal

Substitution of alkaline cyanates by isocyanates allows the preparation of 3-substituted hydantoias, both from amino acids (64) and amino nitriles (65). The related reaction between a-amino acids and phenyl isothiocyanate to yield 5-substituted 3-phenyl-2-thiohydantoiQS has been used for the analytical characterization of amino acids, and is the basis of the Edman method for the sequential degradation of peptides with concomitant identification of the /V-terminal amino acid. 

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Cell type Cell reaction Standard potential (V) Terminal Capacity voltage, (Ah kg 1) Actio (V) Specific energy (Wh kg 1 )... 

Derive the expression for -d[ ] W)]/dt at constant [H+] by making steady-state and long-chain approximations. The fourth reaction is very fast that is, every H202 produced converts U(IV) to U(VI) directly without forming U(V). Termination proceeds by... 

Edman degradation A method of amino acid sequencing in proteins in which successive V-terminal amino acids are removed from the polypeptide chain and identified. 

V. Terminal Hydroxide Derivatives of the s- and p-Block Metals Supported by Poly(pyrazolyl)borato Ligation... 

The synthesis and characterization of a somatostatin receptor-specific peptide H2N-(DPhe)-cyclo[Cys-Phe-(D-Trp)-Lys-Thr-Cys]-Thr-OH, labeled with an indo-dicarbo- and an indotricarbocyanine dye at the V-terminal amino group were described in [34], The ability of these fluorescent contrast agents to target the somatostatin receptor was demonstrated by flow cytometry in vitro, wherein the indotricarbocyanine conjugate led to elevated cell-associated fluorescence on somatostatin receptor-expressing tumor cells. The intracellular localization was visualized using NIR fluorescence microscopy. 

Peptide V-terminal amino acid C-terminal amino acid... 

Table V. Terminal display of the decomposition of the product of two representations of S3-DP-S2...

Figure 25-6 Result of a series of Edman degradations on an /V-terminal Gly-Tyr-His-Ala-peptide...

This may not be completely clear, and it will be well to consider the logic in some detail. Peptides M and N both have /V-terminal valines, and one of them must be the /V-terminal unit. Peptide M overlaps with X and Y, and because X and Y are produced by a cleavage on the carboxyl side of Phe, the X and Y units have to be connected in the order X-Y. Because the other Val is in Y, the /V-terminus must be M. This narrows the possibilities to... 

Exercise 25-19 Eledoisin is a peptide isolated from the salivary glands of eledone, a Mediterranean eight-armed cephalopod. The peptide is a powerful hypotensive agent. Deduce a possible structure from the following information (1) Complete hydrolysis gives equal amounts of ammonia, Ala, Asp, Glu, Gly, lie, Leu, Lys, Met, Phe, Pro, and Ser. (2) No free amino /V-terminal group or free carboxyl C-terminal group can be detected. (3) Chymotrypsin hydrolysis forms two peptides, L and M. Their compositions are... 

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