Chapter VI — 67 — Intracellular Distribution 



packets consisting of monolayer polypeptide chains folded back and forth, 

 or groups of monolayers of shorter length, in size about 50 A on a side ; 

 (&) compact aggregates, due to grouping of the supermolecules, particles 

 that may possibly be visible with the ultramicroscope ; and (c) associations 

 of super molecules and compact aggregates with water channels between. 

 Such groups may be microscopic in size. 



Forces accounting for the grouping of the chains into particles, and of 

 the particles into the various aggregates, are attributed by Sponsler to 

 several types of bonds: primary valence {e.g., cystine) bonds; electrostatic 

 forces due to ions, etc. ; hydrogen bonds ; and van der Waals forces of 

 cohesion. The complex aggregates are probably porous structures, inter- 

 penetrated by water channels, which widen in certain regions to form sub- 

 microscopic vacuoles of varying size. Composing the walls of these vac- 

 uoles, which, according to Sponsler, Warburg has termed "reaction cham- 

 bers," are the active groups which are intimately tied up with respiratory 

 and other vital reactions, including hydration phenomena. 



Frey - Wyssling (1940) has pro- 

 posed a structure for proteins com- 

 bining corpuscular and reticulate proper- 

 ties. His structure is more rigid and con- 

 tinuous than that visualized by Sponsler, 

 consisting of loosely interwoven molecu- 

 lar strands of protein chains (Figure 

 18). The high water content is related 

 to reticulate structure ; fluidity and viscos- 

 ity changes are explained by shifting 

 bonds. 



Fig. 18.-Protein structure pic- BeRNAL (1940) propOSeS that long 



tured by Frey-Wyssling (1940). \ / f f t> 



particles, aggregates of polypeptide chains, 

 are oriented into spindle-shaped bodies termed tactoids which can have 

 either positive or negative charges. 



Any postulated structure must conform with the many extraordinary 

 properties exhibited by protoplasm. Among these are elasticity, plasticity, 

 viscosity (and the ability to vary in this respect with no change in concen- 

 tration), anisotropy, a widely variable imbibitional capacity, rigidity, tensile 

 strength, adhesiveness, thixotropy, and differential permeability. All of 

 these properties are dependent on or related to the amount of water present, 

 and to the types of forces responsible for the retention of water. Because 

 protoplasm may exist in the liquid state, the gel state, and in intermediate 

 states, and may flow or stream, its structure cannot be described in general 

 terms. It neither conforms to a reticulate structure nor a corpuscular one 

 but at times appears to shift from one to the other. Rigidity must be due 

 to the presence of a submicroscopic framework wherein the molecules are 

 coordinated to a lattice structure. Hydrogen bonds may account for such 

 coordination. 



Fluidity, according to modern theory of liquid structure, should result 

 from a breaking down of the lattice to a closer packed structure in which 

 points of abnormal coordination constituting cavities occur. In simple 

 liquids these cavities have been pictured as providing space for the rota- 

 tion of paired molecules in a mechanism postulated to account for viscous 

 flow (Hirschfelder, Stevenson, and Eyring, 1937). If one attempts 

 to apply this theory to fluid protoplasm, he might visualize pairing and 



