1915] 



DAVIS ENZYME ACTION IN MAKINE ALGAE 819 



these in neutral and slightly alkaline solution. This was 

 shown in the formol titrations 1 and in the determination of 

 the nitrogen in the amino acids split off. Albumin was slowly 

 acted upon by Enter omorpha, Mesogloea, and Chondrus. The 

 first and last also hydrolysed the vegetable protein, legumin, 

 to a slight extent — an action that was not shared by Mesogloea. 

 The action of algal powder on the proteolysis of gelatin and 

 albumin in Melt's tubes. — Two lots of Mett's tubes were made 

 up, one containing coagulated egg-white, and the other, 15 per 

 cent gelatin. In each of a series of flasks containing 50 cc. 

 of distilled water, N/200 NaOH and N/200 HC1 respectively, 

 were placed one tube each of egg-white and gelatin. Two 

 grams of the powdered tissue from each of the several forms 

 under investigation were added for enzyme action and the 

 usual percentage of toluene used as an antiseptic. The sev- 

 eral series were kept for two months at room temperature. 

 At the end of that time the albumin tubes in the alkaline solu- 

 tion containing the algal powder of Ulva, Enteromorpha, 

 Chondrus, and Agardhiella showed a slight digestion. The 

 checks in the alkaline solution alone showed swelling. How- 

 ever, although this was indicative of action, it was not definite, 

 since the great length of time the protein was in contact with 

 the complex constituents of the tissue may have been a factor 

 in either causing a slight hydrolysis or a contraction of the 

 albumin. On the other hand, Laminaria, Ascophyllum, Meso- 

 gloea, and Ceramium caused no such action. The gelatin tubes 

 showed no evidences of action even after 60 days. 



The effect of proteinases on the hardening of gelatin. — Dox 

 ( '10) describes a method for testing the hydrolysis of gelatin 

 which consists in keeping the protein in a liquid state during 

 contact with the material being tested for proteolytic activity, 

 then at the end of a stated x>eriod noting whether the gelatin 

 congeals when placed in cold water. This method was used 

 in the following way: Five cc. of 20 per cent gelatin were 

 placed in each of a series of test-tubes, and 5 cc. of the standard 



1 The formaldehyde titrations, as used here, were satisfactory only in a general 

 way, i. c. to show relative rather than exact differences in the amounts of amino 

 acids split off. The differences brought out by the amino-nitrogen determinations 

 are much more exact. 



