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Intracatenary

Intracatenary cross-linked macromolecules occur very often in nature. With the enzyme, ribonuclease, for example, the single peptide chain is cross-linked to itself via four disulfide bridges (Figure 2-5). Another protein, insulin, has, on the other hand, two chains, A and B, of differing composition and peptide residue sequence, joined together by a total of two disulfide bridges. [Pg.54]

The macroconformation of chainlike macro molecules in crystalline polymers is principally determined by two factors, which are inter- and intracatenary forces. Calculation of potential barriers of isolated molecules, that is, in a vacuum, is based exclusively on intracatenarily effective forces (see also Section 4.1.2). Microconformations calculated in this way correspond to an internal energy minimum. According to the equivalence principle, all structural units should adopt geometrically equivalent positions in relation to the crystallographic axes, whereby a monomeric unit, for example, may serve as a structural unit. Thus the regular sequence of microconformations should lead to a regular macroconformation. [Pg.98]

The question is now whether intercatenary effects can lead to changes in the microconformation caused by intracatenary forces, and, if so, to what extent. Of course, intercatenary forces quite definitely affect the mutual packing of main chains, and so, give rise to density differences. But the... [Pg.98]

The conformation of molecules is determined in the gaseous state completely, and in the crystalline state almost completely by intracatenary forces. Solvents interact with solutes, and, thus, can alter their conformations. The effect of this interaction, however, is weak when the solute is surrounded by like molecules. Thus, butane has practically the same conformation energy in the gaseous state, 3.35 kJ/mol, as in the liquid state, 3.22 kJ/mol. [Pg.104]

These bridges are partly between the protofibrils and partly intracatenary. The relative ratio of these types of disulfide bridges is not known. These across-the-board cross-links make wool insoluble. This unusual characteristic is imitated commercially when permanent pleats are incorporated into textiles. By treatment with alkali pK of cysteine at 5), thiols are formed, which subsequently convert to S—bridges (thiol-catalyzed disulfide exchange) ... [Pg.1057]


See other pages where Intracatenary is mentioned: [Pg.54]    [Pg.56]    [Pg.98]    [Pg.99]    [Pg.544]    [Pg.1053]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.223]    [Pg.54]    [Pg.56]    [Pg.98]    [Pg.99]    [Pg.544]    [Pg.1053]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.1091]    [Pg.223]   
See also in sourсe #XX -- [ Pg.52 ]

See also in sourсe #XX -- [ Pg.52 ]




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Intracatenary Forces

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