No. 1, May, 1921] PHYSIOLOGY 93 



nature of certain enzymes; mechanism of enzyme actions; uses and applications of enzymes; 

 and the present status of the enzyme problem. — It is recognized bj- the author that the sub- 

 ject matter may not be presented in a completely rounded and final form; but it is intended 

 to be adequately comprehensive, and to a large degree supplementary to existing wcrks, 

 emphasizing particularly in how far enzyme reactions may be, or have been shown to be, 

 analogous to other chemical changes. The literature of recent work is freely cited. — B. M. 

 Duggar. 



645. Jacoby, M. tjber Bakterien-Katalase. III. [Bacterialcatalase. III.] Biochem. 

 Zeitschr. 95: 124-130. 1919. 



646. Koch, A., ttno A. Oelsner. Uber die Betainspaltung durch die Bakterien des 

 Melasseschlempediingers "Guanol." [The bacterial splitting of betain in the molasses- 

 waste fertilizer Guanol.] Biochem. Zeitschr. 94: 139-162. 1919. — The authors have studied 

 the organisms concerned with the splitting of betain in a commercial "Guanol" fertilizer 

 produced from molasses waste. These comprised various forms to be found in compost, — 

 mold organisms forming trimethylamine and a bacterium which the authors designate as 

 Betainobacler a. The latter was studied in some detail and was found to split of? all the 

 nitrogen of the betain molecule as NH3, using for itself only a small portion. Methyl alco- 

 hol, formic acid, and acetic acid were noted as intermediate disintegration products. — 

 W. W. Bonns. 



647. Nemec, a. tJber die Verbreitung der Glycerophosphatase in den Samenorganismen. 

 [The distribution of glycerophosphatase in seeds.] Biochem. Zeitschr. 93:95-100. 1919. — 

 The author has determined the presence of the enzyme in the seeds of 20 species, using the 

 method of Neuberg and Karczag. The substrate used was a 1 per cent solution of sodium 

 glycerophosphate (Merck), the total P2O5 being determined, and macerated seed material 

 was allowed to act upon the phosphate solution under controlled conditions. Results are 

 given in P2O6 split off. The necessary controls were determined. The values given in the 

 author's table show that of the seeds used the cereals possess the least hydrolytic activity. 

 Legumes show high enzyme content, differing considerably with the species. Plants of Lens 

 and Pisum were more active than those of Lupinus and Vicia. The crucifers (Brassica, 

 Raphanus, and Sinapsis) are especially rich in the enzyme, the latter splitting off more than 

 41 per cent PaOs. The maximum activity was observed in the soy bean, which hydrolyzed 

 almost 50 per cent of the glycerophosphate supplied. In general, seeds rich in oil are higher 

 in enzyme activity of the kind here studied than the albuminous seeds, and the latter in turn 

 have greater hydrolytic power than starchy seeds. — The fact that the P2O6 set free in no case 

 exceeded 50 per cent of the amount present in the substrate leads the author to the belief that 

 the enzyme present acts only on the naturally occurring d-glycerophosphoric acid. Thermo- 

 lability of the enzyme at 100°C. was established. — W. W. Bonns. 



648. Northrop, John H. The influence of hydrogen ion concentration on the inactivation 

 of pepsin solutions. Jour. Gen. Physiol. 2: 465-470. 1920. — Pepsin in solution at 38°C. was 

 found to be most stable at a hydrogen-ion concentration of Ph 5.0. An increase above this 

 point resulted in a slow increase in the rate of destruction of the pepsin, while a decrease 

 resulted in a rapid increase in the rate of destruction. Neither the impurity of the enzyme, 

 nor the anion of the acid affected appreciably the rate of destruction. There seemed to be no 

 relation between optimum range of hydrogen-ion concentration for digestion and the destruc- 

 tion of the enzyme. — Otis F. Curtis. 



649. Northrop, John H. The effect of the concentration of enzyme on the rate of diges- 

 tion of proteins by pepsin. Jour. Gen. Physiol. 2: 471-498. 1920.— The rate of protein diges- 

 tion is not always proportional to the total concentration of pepsin. It is suggested that this 

 may be due to inactivation of some of the enzyme by combination with some product of the 

 reaction, perhaps peptone, and that this inactivation is quantitatively expressed by the 

 law of mass action. The rate of reaction is, therefore, proportional to the quantity of active 



