CELLULOSE-PROTEIN COMPLEXES 233 



(1953) and Wood (1954) have shown that a polysaccharide frac- 

 tion resembhng chondroitin sulfate is essential for the maintenance 

 of some of the physical properties of collagen fibers. Similarly, Hall 

 et al. (1952) and Hall (1955) have demonstrated that the removal 

 of polysaccharides from elastic fibers leads to a marked change in 

 the resistance of the fiber to chemical and enzymic attack. More- 

 over, for these fibers, particularly in the aorta, it has been claimed 

 (Saxl, 1957) that pathological degradation is bound up with the 

 topographical concentration of polysaccharides. Excessive resist- 

 ance of connective tissue fibers to chemical attack has been ascribed 

 to variations in the content of associated polysaccharide (Hall and 

 Reed, 1957; Keech, 1958). Stabilization of this kind is regarded by 

 Yu and Blumenthal (1958) as due to the existence of complexes 

 between proteins and pol\ saccharides. 



The more recent evidence in favor of a close relationship between 

 cellulose and proteins in the cell walls of plants comes from four 

 main sources. These will be dealt with separately below. 



Cellulose-Protein Complexes in Mammalian Tissue 



The recent demonstrations of the presence of cellulose in mam- 

 malian tissue (Hall and Reed, 1957) and of its association with pro- 

 tein in healthy and pathological skin (Hall et al, 1960; Hall and 

 Saxl, 1961 ) gives a specific lead. The fibers concerned were first 

 observed as highly birefringent inclusions in the alkaline degrada- 

 tion products of collagen (Burton et al, 1955; Hall et al, 1960). 

 They were reported to be rich in polysaccharide and highly resistant 

 to chemical attack, and the polysaccharide has been identified as 

 cellulose for the following reasons : ( 1 ) The x-ray diagram is indis- 

 tinguishable from that of cotton cellulose. (2) The fibrils of the 

 polysaccharide appear to be uniaxial with refractive indices of 1.596 

 and 1.525, very close to those of ramie fibers. (3) Paper-partition 

 chromatography of hydrolysates reveals the presence of only traces 

 of sugars other than glucose, and in particular no traces were found 

 of glucosamine, galactosamine, glucuronic acid, or galacturonic acid. 

 (4) The polysaccharide is soluble in Schweizer's reagent but not in 

 hot water, alkali, or boiling dilute sulfuric acid. (5) The electron 

 microscope appearance and the electron-diffraction diagram closely 

 resemble those of cellulose. 



