Pyrogallol test

Peroxidase activities were also shown to occur during the bean rust infection process (Mendgen, 1975). In reed canary grass (Phalaris arundinacea L ), peroxidase was identified with the pyrogallol test (Vance and Sherwood, 1976). 

The purified enzyme had practically no catalase or peroxidase activity, as measured by the spectrophotometric method of Chance (1) and by the pyrogallol test (2), respectively. 

Parameter Unils used in pyrogallol test Kinetic units... 

This value is higher than that obtained by most workers using the classical pyrogallol test and crystalline enzyme preparations. " But this was to be expected in view of the discrepancy between the kinetics of the primary oxidation of pyrogallol and the appearance of purpurogallin described above. 

A useful modification of the pyrogallol test is described in a paper of Keilin and Hartree (7). 

Plicnoh.— If it is a free phenol, ether will extiact it from its ac ueous solution. If it is present in alkaline solution, the solution should first be saturated with cat bon dioxide. (n.B.—The alkaline solutions of catecliol, quinol and pyrogallol daiken rapidly m the air.) The following tests should then be applied. 

Add dilute ammonia solution until a faint permanent turbidity is obtained and then clear the solution by careful addition of a little dilute nitric acid. To the boiling solution add a slight excess of a solution of pure pyrogallol in air-free water. Continue boiling for a short time, test for completeness of precipitation and filter. Wash the precipitate with 0.05M nitric acid and then with water. Dry at 105 °C and weigh as Bi(C6H303) (Section 11.20). 

Different histochemical tests have been used for peroxidase identification. Benzidine (4.33) has been used as a staining reagent, as well as guaiacol (4.34) and pyrogallol (4.35). However, until the 1970s, no reliable methods were known that allowed a sharp discrimination between oxidase and peroxidase activities (Maehly and Chance, 1954). Harkin and Obst (1973) reported the syringaldazine (4.36) histochemical test for peroxidase. This test permitted the proof of exclusive peroxidase participation in the lignification process. 

---