805 EXPERIMENT STATION RECORD. 



optimum temperuture is about 57.5° C. The amount of eitJaer enzym present 

 varies with the age of the mold but amygdalase always predominates. The 

 greatest enzymatic activity was noted in 4-day-old cultures. The ratio of the 

 two enzyms varied widely in other molds, one enzym being present in excess 

 at one time, the other at another time. 



Studies on enzym action. — VI, The specificity of lipase action, K. G. Falk 

 {Jour. Amer. Chem. Soc, 35 {1913), No. 5, pp. 616-624) .—In this paper the 

 action of methyl alcohol, ethyl alcohol, acetone, glycerol, and glucose on the 

 activity of the lipase preparation was studied, and an explanation of the 

 selective activity of lipases based upon the results obtained is given. 



It is shown that " solutions of methyl alcohol, ethyl alcohol, and acetone ex- 

 erted inhibiting actions on the hydrolysis of ethyl butyrate by a castor bean 

 lipase preparation under comparable conditions, the amount of inhibition in- 

 creasing with the concentration. Solutions of glucose and glycerol showed no 

 inhibiting action except perhaps in the most concentrated solution. The view 

 is suggested that simple esters exert an inhibiting action on lipase similar to 

 that exerted by simple alcohols, and that higher esters (such as the glycerol 

 esters) exert less inhibiting action similar to that exerted by glycerol. 



"The lipolytic activity of the castor bean preparation was tested with solu- 

 tions of methyl acetate, ethyl acetate, ethyl butyrate, and glyceryl triacetate 

 (triacetin) of considerable ranges of concentration, and the results were 

 correlated and explained by the aid of the theory outlined. Possible applica- 

 tions of the theory to the action of other hydrolyzing agents on esters compared 

 with the action of lipase, to lipases of animal origin, and to the effect on the 

 determination of the activity of lipase under various conditions of added sub- 

 stances, were mentioned. This theory, together witii the specific actions of 

 various groupings in the (presumably) protein molecule of lipase on the hydroly- 

 sis of esters as demonstrated [in the abstract below], will probably explain 

 most, if not all, of the selective actions of the lipases. Finally, the use of tri- 

 acetin as substrate for testing lipolytic activity is recommended." 



Studies on enzym action. — VII, A further study of the hydrolytic action 

 of amino acids on esters, M. L. Hamlin {Jour. A7ner. Chem. Soc, 35 {1913), 

 No. 5, pp. 624-632). — " Glycin, glutamic acid, and aspartic acid exert a varying 

 lypolitic action on methyl, ethyl, glyceryl tri- and phenylactates, ethyl butyrate, 

 and ethyl and phenyl benzoates. If these be arranged in the order of decreas- 

 ing amounts of hydrolysis, the order will be different in the 3 cases where the 

 action is caused by water, by glycin, and by glutamic or aspartic acids. This in- 

 dicates selective action. The effect of sodium chlorid, sodium sulphate, and mag- 

 nesium sulphate in solutions from 0.2 to 2 normal is not marked or consistent 

 enough to be important for this work. The hydrolytic action of solutions of 

 glycin and acetic acid on methyl acetate and ethyl butyrate is less than that of 

 corresponding solutions of acetic acid alone; this difference is proportionately 

 much less with ethyl butyrate." 



Comparative study of the cleavag-e of saccharose by various acids in the 

 presence of yeast invertase, G. Bertband and M. and Mme. Rosenblatt {Ann. 

 Imt. Pasteur, 26 {1912), No. 5, pp. 321-831; ahs. in ZervtU. Expt. Med., 2 {1912), 

 No. 15, pp. 684, 685). — The hydrolyzing power of various organic and inorganic 

 acids in the presence of invertase, and possibly also of many other soluble 

 enzyms, does not depend entirely upon the hydrogen ion concentration. It is 

 also dependent upon the nature of the acids, i. e., the anions. 



Some properties of koji-diastase, G. Kita {Jour. Indus, and EngPn. Chem., 

 5 {1913), No. 3, pp. 220-222) .—'' Though koji may contain 2 different sacchari- 

 fying enzyms, viz, amylase and glucase, the total quantity of the glucose in a 

 saccharified solution could not be produced from maltoseby the action of glucase 



