Colloidal ChemistryKapillarchemie, eine Darstellung der Chemie der Kolloide und Verwandter Gebiete. Herbert Freundlich

B. E. Livingston
1910 Botanical Gazette  
I5I and the fermentable substances. To BERTRAND we owe the introduction into science of the term oxidase. The adoption of this general term was based upon the discovery and characteristics of laccase and tyrosinase. The chapter concludes with a classification of oxidases and special reference to the sources, preparation, and characteristics of laccase, tyrosinase, aldehydase, and the purin oxidases. The third chapter is devoted to the peroxidases and catalases. The weight of opinion is inclined
more » ... opinion is inclined to the conception that peroxidases are substances capable of forming unstable peroxids from hydrogen peroxid, by double decomposition or by combining directly with the hydrogen peroxid to form unstable holoxid (TRAUBE) derivatives, possessing greater powers of oxidation than hydrogen peroxid. BACH and CHODAT'S conception of an oxidase consisting of a mixture of peroxidases and peroxid-forming substances (oxygenases) would make the peroxidases the more important agents in plant and animal oxidations, and would relegate the oxidases to an insignificant position in such oxidations, if indeed they function as enzymes at all. In the author's opinion the objections which have been recently urged against the true enzymatic nature of oxidases are well taken. A considerable amount of evidence is brought together to show the importance of iron, copper, and manganese as coenzymes to oxidizing ferments. According to BERTRAND, manganese is the really active element of the oxidases, so far as the activation and transfer of oxygen is concerned. EULER and BOLIN have found that laccase has no action on hydroquinone in the absence of manganous salts, and therefore they suggest that laccase owes its activity to the presence of such salts. In this connection it is interesting to note that in a paper by BACH,2 more recent than the above monograph, he claims to have obtained a tyrosinase which will oxidize tyrosin to the red stage and is free from both iron and manganese. He concludes, therefore, that manganese and iron salts are in no way necessary for oxidase activity. One of the most valuable features of the monograph is the comprehensive list of references to the literature.-CHARLES 0. APPLEMAN. Colloidal chemistry The newer plant physiology should welcome the appearance of FREUNDLICH'S books on colloidal chemistry, or capillary chemistry, as he terms it. This is the first attempt to bring together our knowledge of this youngest and most difficult branch of physical chemistry. It puts the physiologist immediately in touch with the present status and most important literature of a subject which seems destined to play at least as important a role in the study of vital phenomena as 2 BACH, A., Zur Theorie der Oxidasewirkung. Ber. Deutsch. Chem. Gesell. 43:362. I9IO. 3 FREUNDLICH, HERBERT, Kapillarchemie, eine Darstellung der Chemie der Kolloide und verwandter Gebiete. 8vo. pp. viii+591. figs. 75. Leipzig. i909. This content downloaded from 129.
doi:10.1086/330310 fatcat:wtxbdbumobeyvav2ldarl7cvs4