APPAJ^ATUS FOR MEASUREMENT OF OXIDASE AND 

 CATALASE ACTIVITY. 



By R. B. HARVEY. 



(From /lie Bureau of Plant Iiidusli'V, Uiiilcd Slates Drparlmeiil of Agrienlttire, 



\]' ashinglon.) 



(Received for publication, November 25, 1919.) 



On account of some undesirable features of the simplified Bunzel 

 oxidase apparatus,^ the author has designed a simple apparatus 

 (Fig. 1) incorporating the advantages of both the simplified Bunzel 

 apparatus and the original design. - 



The simplified Bunzel oxidase apparatus makes no provision for 

 the absorption of CO2 other than by the reagents used. In some 

 reactions the CO2 production cannot be disregarded without error. 

 Bunzel gives data on this point.'- 



This source of error is removed in the new design by using a 

 caustic tube and alkali to absorb the CO2 produced during (he 

 reaction. 1 cc. of 0.1 n alkali is placed in the caustic tube, and on 

 shaking the apparatus the liquid surges back and forth beneath the 

 tube, forcing the air over the alkali. 



The apparatus has a volume of 68 cc. measured to the zero of the 

 middle graduated tube. The volume of glass comprising the boat 

 is 3 cc, to which is added 1 cc. of alkali, 2 cc. of plant juice or dilu- 

 tion, and 5 cc. of reagent and buffer solution, totaling 11 cc. In 

 case it is desired to use the apparatus without the alkali tube, the 

 total volume of liquid should be 11 cc. This allows 57 cc. of air 

 space in which a difference of 1 cm. between the mercury levels in 

 the manometer corresponds to a change of 0.75 cc. in volume at 760 

 mm. pressure. The manometer is graduated for both positive and 

 negative pressures. 



The apparatus can be conveniently used for the determination of 

 catalase activity. 



1 Bunzel, H. H., /. Biol. Chem., 1914, xvii, 409. 



2 Bunzel, H. H., /. Am. Chem. Soc. 1912, xxxiv, 303. 



2. S3 



