Terminal groups location

Terminal group location Surface or interior Attachment networks + + + —... 

Very recently, Topp et al. [29] probed the location of the terminal groups of a dendrimer of seventh generation using SANS. These authors concluded that the terminal units as well as nearly half of its monomer units are located in the vicinity of the surface of the molecule. This is in contradiction to the results derived from simulations (see Sect. 2). In addition, it is difficult to reconcile this result with the findings of [23,24] which showed that flexible dendrimers have the maximum density at the center of the molecule. 

Note 1 See Fig. 36. The mesogenic groups can be located along the chains of the molecule (a) or can occur as terminal groups (b). 

BAs are a group of acids with a steroidal ring structure and a terminal carboxylic group located in the side chain (Fig. 5.4.1), and represent the major end products of cholesterol catabolism [2]. 

The acid-base behavior of peptides (10) is determined by the free a-amino group on the N-terminal residue, by the free a-carboxyl group on the C-terminal residue, and by the ionizable R groups located at intermediate positions. The pK values of the terminal a-carboxyl groups are somewhat higher and those of the a-amino groups somewhat lower than those of the corresponding free amino acids (Table 1) (11). 

The synthesis of pressor amines in the body may convincingly be considered to begin with the essential amino acid, phenylalanine as illustrated in Table I. Gurin and Delluva (86) have reported that phenylalanine labeled with tritium, or containing C14 located both in the carboxyl group and in the position adjacent thereto, was converted in the rat to radioactive adrenaline. Only one C14 atom was present in the side chain and it was in the terminal group bearing the secondary amine (86). However the intermediate steps in the synthesis are by no means so certain, nor does this necessarily preclude other paths of synthesis. 

Cytochrome Cj contains a c-type haem as prosthetic group in its wedge-shaped N-terminal domain located in the inter-membrane space. This extrinsic domain is anchored to membrane by a transmembrane helix at the C-terminal end (residues 204 to 222 in bovine bc ). This helix runs alongside cytochrome b and can be removed by mild protease treatment or gene truncation to produce a protein fragment (Hase et al., 1987 Li et al., 1981). 

The comparison of the amino acid sequence of the above-mentioned bitter peptides shows a large proportion of hydrophobic amino acids in each peptide. And the amino acid sequence of peptides also plays an important role in the intensity of the bitter taste. For example, the bitterness of Phe-Pro is more intense than that of Pro-Phe, and the bitterness of Gly-Phe-Pro is more intense than that of Phe-Pro-Gly (23). C-terminal groups of all bitter peptides in pepsin hydrolysates of the above-mentioned soy protein were characterized by the location of the Leu residue (14-17). The research on the relationship between the structure and bitter taste intensity of Arg-Gly-Pro-Pro-Phe-Ile-Val (BP-Ia) showed that Pro and Arg located on center and the N-terminal site, respectively, played an important role in the increment of bitter taste intensity besides the hydro-phobic amino acids located on C-terminal site (24-26). This may indicate that the peptide molecular structure formed by the arrangement of Arg, Pro and hydrophobic amino acid residues contributes to the bitter taste intensity of the peptide. 

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