Tricomplex systems

In tricomplex systems (Ch. X 6 p.415) however this no longer holds. Here the amphoions of the phosphatide preparation form the reacting component of the mixture, and the phosphatidic anions present are only a nuisance. Therefore the said tricomplex systems are the more typical the higher the reciprocal hexol number, that is the fewer phosphatidic anions are present. 

After the dicomplex systems the unicomplex ones will be cursorily discussed and finally we shall deal with the tricomplex systems. 

It may also be remarked that in the unicomplex and tricomplex systems a protein is not active with the excess of the one kind of charge over the other but with them what matters is the electric multipole character of the protein. A too large excess is with them even a hinderence for the occurrence of the systems in question. 

From the characteristic that these three ion types simultaneously play off complex relations against each other, these systems have been called tricomplex systems. Now the workii hypothesis presents itself more or less spontaneously that — at least in non complicated cases — the cation puts itself in complex relation to the negatively charged ionised group of the amphoion, the anion on the other hand to the positively charged ionised group of the amphoion. 

Compare Fig. 50 in which the uni-, di- and tricomplex systems have been symbolised as simply as possible by the schematic figures I, II and III. In them cations and... 

This is not the case with the tricomplex systems where the three complex relations indicated differ in intensity from each other. This is not in fact completely manifest in this scheme because the complex relations between cation and anion are merely indicated in a different way, namely by dots, those between each of them and the charges of the twitter ion again by dashes. 

With very simple cations, for example, Ca and Li — with which tricomplex systems are also possible — this complication can left out of account. 

It is characteristic of tricomplex systems that here the specific charge elements of the colloid ions and micro ions taking part play a part to a very large extent. Before we go into this more fully a general consideration may first be put forward in which we take the above given simple working hypothesis as our starting point. 

First of all one must bear in mind then that one can also join the ions which occur in the symbol of the tricomplex systems to the two schemes for the uni- and dicomplex systems. 

In the tricomplex system besides b there occur two other complex relations c and d and it is thereby clear that as regards the question whether in a given case a tricomplex system will be produced or not, it will now depend on the intensity of the complex relations in the tricomplex system compared with those in the unicomplex and dicomplex systems together. 

Fig. 51. Formation of a tricomplex system from (or decomposition to) a unicomplex and a dicomplex...

Ifc-I-ddicomplex system. In this pne should bear in mind that the schematic pictures have only formal significance and merely depict the complex relations between four charges while in reality these patterns ought to be applied to the actually existing charge distribution in these systems, for example, to a linear arrangement along the kinked macromolecule distributed in space. 

In any case it becomes apparent that the realisation of tricomplex systems will be favoured when the complex relations c and d are more intense than a and especially than 6. 

The above formulated condition c + d a + b is not the only one since c + d itself must also exceed a certain minimum value if one is in fact to arrive at the separation of a tricomplex system. The great significance of a small equivalent weight for the realisation of dicomplex flocculations or coacervations (see p. 374, 2r and... 

Nevertheless the affinity of Ca for the phosphate group of the lecithin is still appreciably greater than for the carboxyl group of the pectate (c ) 6). Formation of a tricomplex system is therefore still possible but this manifests itself only in an intensification of the turbidity, in the presence of lecithin. 

In the combination lecithin + nucleate + Ca the factors are now no longer at all favourable for the formation of a tricomplex system. 

Or escape observation by the method employed here (sol -f- salt I salt II) if the bonds in the tricomplex system are very weak because the two ions of salt I and salt II, which do not take part in tricomplex formation (NO3 or Cl of salt I and K of salt II) form an indifferent salt which suppresses a very weak complex flocculation. Compare small print on p. 432 from which it appears that such a very weak tricomplex flocculation is possible with phosphatide -h Ca - - I. ... 

In the preceeding subsection we have spoken without further comment of the greater or less intensity of complex relations between micro ions and colloid ions. Naturally what was meant was actually the comparison of the maximum intensities of these complex relations obtainable with the micro ions in question. Indeed, just as this is already the case in the dicomplex systems, colloid cation + micro anion or colloid anion + micro cation, the statement, that the intensity of the complex relations formed by a micro cation is still a function of the concentration, also holds for the tricomplex systems. 

This is possibly of importance for biology since it appears from it that at pH values of 6 — 8, the so-called acid proteins can still react sufficiently as amphoions (multipole ions) to make it possible that tricomplex systems could occur in the conditions of natural media. 

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