70 The Structure of Protoplasm 



the number and distribution of the polar residue end groups. If the 

 particles could come together, face to face, a rather solid protein 

 complex would be formed; but with the large number of phospho- 

 lipids and smaller organic molecules present in protoplasm it seems 

 likely that some of them would intervene and prevent close face-to- 

 face attachment. We would expect, then, a rather wide separation of 

 perhaps 25-50 A due to the presence of the long hydrocarbon chains 

 of the phospholipids on some faces and less separation due to the 

 smaller organic molecules on other faces. It should be pointed out 

 also that inorganic ions may prove to be of considerable importance 

 in the formation of loose and transitory aggregates (122). 



If we allow ourselves to speculate somewhat concerning the in- 

 ternal construction of the larger particles consisting of an aggre- 

 gation of perhaps thousands of these complex, conjugated proteins, 

 it seems reasonable to think that rather compact regions may occur 

 in addition to regions in which, either due to the overlapping of 

 particles or to loose aggregation (122), submicroscopic vacuoles oc- 

 cur. It is possible that it is in these regions that many of the "vital" 

 activities take place. In other words, the complex aggregates of many 

 simple 50 A particles are likely to be relatively porous with some 

 small and some large submicroscopic vacuoles. These loose, spongy, 

 complex aggregates may consist of a thousand component protein 

 particles, interpenetrated with water channels which widen here 

 and there to form the internal vacuoles, or "reaction chambers" as 

 they have been called (123). The walls of these "chambers" are 

 the faces of the protein particles to which fatty materials and res- 

 piratory prosthetic groups may be attached, probably in some spe- 

 cific pattern. The "chambers" may be relatively isolated from one 

 another within the same complex and are likely to vary somewhat 

 in their activity towards a substrate molecule. It seems possible 

 that the substrate molecule may be transformed in one manner in. 

 one "reaction chamber" and in quite a different manner in another. 

 By this means a channeling of reactions may occur which would not 

 take place if these materials were mixed and distributed in any 

 other fashion. Such a definite arrangement may be considered as one 

 phase of orgayiization in the particle as a whole. 



The existence of complexes, whose activity depends upon the 

 integrity of the whole and whose organization is relatively easily 

 disturbed, has been demonstrated recently (14, 124, 125). The need 

 for such particular specific internal arrangements between the res- 

 piratory components has been sensed for some time (111) , and it 



