Collage x Hydrolysis 



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215 (2175) 



The hydrolysis of collagen by trypsin. 

 By ARTHUR W. THOMAS and F. L. SEYMOUR-JONES. 



[From the Department of Chemistry, Columbia University, 

 New York City.] 



The generally accepted statement that collagen is not hy- 

 drolyzed by trypsin unless previously swollen in acid or alkali, 

 shrunk in hot water, or treated with pepsin, rests entirely on 

 qualitative work by Kiihne and Ewald 1 in 1887 and 1890. 



Using finely sifted hide powder as a source of collagen, we 

 found that it was readily digested by trypsin in concentrations 

 of the protease exceeding 10 mg. per liter. The hide powder 

 was treated in 10 c.c. conical graduated centrifuge tubes with 

 buffer solutions at various hydrogen ion concentrations, centri- 

 fuged, and the volume of powder measured. The buffer was 

 then replaced by a trypsin solution made up in a buffer of 

 known P H , and digestion carried on, with continuous shaking, 

 at 40.00°. By suitable variation of the buffer we found that 

 the tryptic hydrolysis was not affected by pretreatment of the 

 collagen at different P H 's between 1.1 and 8.9 and that the opti- 

 mum reaction for the hydrolysis was at P H 5.9. The time- 

 hydrolysis curve for trypsin-collagen is of the same nature as 

 with trypsin and proteins in general ; since here the substrate is 

 insoluble though hydrated, tryptic action appears to take place 

 at the surface of the substrate particles, whether these be coarse- 

 ly or colloidally dispersed. The degree of hydrolysis increases 

 with increasing concentration of trypsin and decreasing size of 

 hide powder particles. Complete hydrolysis was not reached in 

 tour periods of 20 minutes each, the experiment being then stop- 

 ped owing to increasing hydrolysis in the control (hide powder 

 and buffer solution without trypsin). 



The shape of the hydrolysis-time curve suggests that the reac- 

 tion is very slightly reversible. Experiments on pelt, using con- 

 centrations of trypsin up to 0.4 per cent., showed measurable 



i Verh. d. Naturhist. Med. Ver. in Heidelberg, (X.F.) 1887, i, 451. ibid., 

 (N. F.), 1887, i, 451; Z. f. Biol, (N. F. 8), 1890, xxvi i. 



