Electron microscopy; proceedings of the Stockholm Conference, September, 1956 . electronmicrosco00euro Year: 1957 226 G. LELLI AND G. ARANGIO-RUIZ Table 1. The damage of collagen fibrils through papain treatment. Table 2. Controls in distilled water. Papain Temp. Time Effects Powder 24 C 24 h Saturated solution 24° C 20' 24 h - + + + 2 °o solution 50'C 1 h + 5h + + 14 h 24 h + + + + + + + + Biochemically the proteolytic action of papain, like that of pepsin, leads to the formation of peptones. By means of activators, particularly hydrocyanic acid, its action becomes intensified, leading to th
Electron microscopy; proceedings of the Stockholm Conference, September, 1956 . electronmicrosco00euro Year: 1957 226 G. LELLI AND G. ARANGIO-RUIZ Table 1. The damage of collagen fibrils through papain treatment. Table 2. Controls in distilled water. Papain Temp. Time Effects Powder 24 C 24 h Saturated solution 24° C 20' 24 h - + + + 2 °o solution 50'C 1 h + 5h + + 14 h 24 h + + + + + + + + Biochemically the proteolytic action of papain, like that of pepsin, leads to the formation of peptones. By means of activators, particularly hydrocyanic acid, its action becomes intensified, leading to the formation of three times the amount of aminoacids such as tyrosine, tryp- tophane, leucine, glycocole, alanine, proline and arginine as in the proteinic decomposition due to trypsin. The action of papain thus stands between that of trypsin and pepsin (1). Papain develops its optimal activity at pH 5 (trypsin's optimum pH 9) with a rapid decrease towards the acid side, and its solutions are usually neutral. The collagen used in these studies was obtained by lacerating in distilled water fragments of guinea pig skin and tendons of rabbits and calves. The papain was obtained from the Nutritional Biochemicals Corporation, Cleveland, Ohio, and was used without activators. In some cases we used 'papaiotin' (E. Merck A. G., Darm- stadt) which is the almost pure ferment extracted from Carica papaya. As according to Willstaetter & Grassmann (7) papain has an optimal temperature of 65-70 C we have experi- mented with different temperatures without, however, reaching such degrees as would be able to produce directly changes in the collagen fibrils (3). The properly lacerated material was washed several times in double distilled water after treatment with the enzyme and then chromium shadowed before being examined in the electron microscope. The tables 1-2 summarize the results obtained. It is clear that the most severe lesions right up to the almost complete destruction of the fibrils
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