30 Ch. M. Lapiere 



Fractionation studies of soft and calcified tissues separate the collagen in fractions 

 of different organization according to their age. These fractions seem to be related 

 one to the other in a process of maturation quite similar in both tissues. 



Enzymatic breakdown of the collagen in skin and bone is demonstratable in tissue 

 culture. There exists identical difficulty in isolating a coUagenolytic enzyme from 

 living soft and calcified connective tissues. 



Acknozc'ledgements 



This work has been supported in part by Grant AM 07250 of the National In- 

 stitute of Arthritis and Metabolism of the U.S. Public Health Service. 



The author wishes to acknowledge the many valuable discussions with Drs. 

 Jerome Gross and Marvin Tanzer and the criticism of the manuscript by the latter. 



References 



Belanger, L. F., J. RoBicHON, B. B. MiGicovsKY, D. H. Copp, and J. Vincent: Resorption 



without osteoclasts (osteolysis). In Mechanisms of Hard Tissue Destruction. Sognnaes, 



R. J. (ed.) Washington: Amer. Ass. Advanc. Scl. 1963, p. 531. 

 Currey, J. D.: Three analogies to explain the mechanical properties of bone. Blorheol. 2, 



1 (1964). 

 Eastoe, J. E.: The organic matrix of bone. In The Biochemistry and Physiology of Bone. 



Bourne, G. H. (ed.). New York: Academic Press 1956, p. 81. 

 Flanagan, B., and G. Nichols: Direct measurements of human bone metabolism In normal 



and hyperparathyrold subjects. Clin. Res. 12, 266 (1964). 

 Gaillard, p. J.: Parathyroid gland and bone in vitro. Develop. Biol. 1, 152 (1959). 

 Glimcher, M. J.: Molecular biology of mineralized tissues with particular reference to bone. 



Rev. mod. Phys. 31, 359 (1959)'. 



— The organization of collagen In bone. In Symposium International sur la blochlmie et la 

 physiologic du tissu conjonctlf. Delaunay, A. (ed.). (In press.) 



— , A. J. Hodge, and F. O. Schmitt: Macromolecular aggregation states In relation to mine- 

 ralization: the collagen hydroxyapatite system as studied in vitro. Proc. nat. Acad. Scl. 

 43, 860 (1957). 



— , and S. M. Krane: Studies of the Interaction of collagen and phosphate. I. The nature of 

 Inorganic orthophosphate binding. In Radioisotopes and Bone. Lacroix, P., and A. M. 

 BuDY (eds.). Oxford: Blackwell Scientific Publications 196x2, p. 393. 



GoLDHABER, P.: The effect of hyperoxia on Bone Resorption In Tissue Culture. A. M. A. 

 Arch. Path. 66, 635 (1958). 



Green, N. M., and D. A. Lowther: Formation of collagen hydroxyprollne in vitro. Blochcm. 

 J. 71, 55 (1959). 



Gross, J.: Studies on the formation of collagen. I. Properties and fractionation of neutral 

 salt extracts of normal guinea pigs connective tissue. J. exp. Med. 107, 247 (1958 a). 



— Studies on the formation of collagen. II. The influence of growth rate on neutral salt 

 extracts of guinea pigs dermis. J. exp. Med. 107, 265 (1958 b). 



— Studies on the formation of collagen. III. Time-dependent solubility changes of collagen 

 in vitro. J. exp. Med. 108, 215 (1958 c). 



— On the significance of the soluble collagens. In Connective Tissue, Thrombosis and Athero- 

 sclerosis. Page, I. H. (ed.). New York: Academic Press 1959, p. 77. 



— An Intermolecular defect of collagen In experimental lathyrism. Biochlm. blophys. Acta 

 71, 250 (1963 a). 



— Comparative biochemistry of collagen. In Comparative Biochemistry, A Comprehensive 

 Treatise. Florkin, M., and H. S. Mason (eds.). New York: Academic Press 1963 b, p. 307. 



— , and Ch. M. Lapiere: CoUagenolytic activity In amphibian tissues: A tissue culture assay. 



Proc. nat. Acad. Scl. 48, 1014 (1962). 

 Hancox, N. M., and B. Boothroyd: Structure-function relationships In the osteoclast. In 



Mechanisms of Hard Tissue Destruction. Sognnaes, R. J. (ed.). Washington: Amer. Ass. 



Advanc. Scl. 1963, p. 497. 



