1903.] The Hydrolysis of Fats in vitro by means of Steapsin. 



" The Hydrolysis of Fats in vitro by means of Steapsin." By 

 Dr. J. LEWKOWITSCH and Dr. J. J. R. MACLEOD, Mackinnon 

 Scholar. Communicated by Professor E. DIVERS, F.R.S. 

 Received May 11, Read May 28, 1903. 



A few months ago, one of us (J. L.) stated* that he had made a 

 series of experiments in which lipase was allowed to act on cotton- 

 seed oil, and that he had only been able to obtain hydrolysis amounting 

 to 3 per cent. Dr. Macleod then suggested that it would be of con- 

 siderable interest to ascertain the extent to which steapsin could carry 

 the hydrolysis under the same conditions. We, therefore, decided to 

 investigate this question conjointly, and we are now in a position to 

 show beyond doubt that steapsin is capable of hydrolysing (saponifying) 

 fats outside the organism to a very great extent. As this fact appears 

 to us of considerable physiological importance, inasmuch as the 

 quantitative experiments have hitherto been made almost entirely on 

 monobutyrin and simple esters,! we publish this preliminary notice 

 without referring to the literature in extenso. This will be done after 

 the completion of the experiments we have in hand. 



Preparation of the Steapsin Solution. 



The steapsin solutions A and B (see table) were prepared from fresh 

 ox pancreas. The pancreas was freed of fat, minced, and 200 grams 

 ground up in a mortar with water. In the case of preparation A, 

 * 1 per cent, of mercuric chloride was added, and in B some thymol. 

 The preparations were then digested in the incubator at body tem- 

 perature for 20 hours, f Next they were filtered, and the filtrate 

 examined for steapsin by vigorously shaking 2 3 c.c. in a test tube 

 with a few drops of filtered butter fat, adding a drop of an alcoholic 

 solution of phenolphthalein and then decinormal caustic soda solution, 

 till a deep red colour was obtained. Exactly the same mixture was 



* ' Jour. Soc. Chem. Ind..' 1903, p. 67. 



f Nencki (" Spaltung der Saureester der Fettreihe und der aromatischen Verbin- 

 dungcn im Organismus und durcli das Pancreas," ' Arch, fur exper. Path. u. 

 Pharmak.,' vol. 20, p. 367) tested the action of an aqueous extract of pancreas on 

 mutton fat, but found hydrolysis to proceed only to about 20 per cent. By adding 

 bile to the digest the saponification amounted to about 60 per cent. Pawlow (' The 

 Work of the Digestive Glands, 1 translated by W. H. Thompson, London, 1902) also 

 records determinations by Dr. Walther (pp. 29, 39) of the steatolvtic action of 

 pancreatic juice obtained from a fistula, but the results do not give us an estimate 

 of the actual amount of hydrolysis effected. They were used by the workers for 

 comparative observations. 



J These are the methods recommended by Ferd. Klug (" Ueber Grasentwicke- 

 lung bei Pankreasverdauung," 'Pfluger's Archiv,' vol. 70, p. 329, 1898). 



