Is Uricase Present in Soy Beans?

Abstract

Némec (1920) reported that a very “active” enzyme, uricase, is present in soy beans, and formulated an oxidative process of decomposing uric acid with the formation of urea. Horvath 2 (1926) remarks that this process may be a possible source of error in the determination of urea nitrogen in blood by the aeration urease method. Since this method has gained wide popularity, it is important to know whether uricase is present or absent in soy beans. Takeuchi and various other workers have reported that the aqueous extract of soy bean had no action on uric acid and many other protein derivatives.

Experiments were arranged under conditions exactly the same as those described by Némec. 1 Potassium urate was dissolved in boiling water (0.3 gm. in 100 cc.). Chinese yellow soy beans were ground to a fine powder, 5 grams of which were poured into an Erlenmeyer flask. Then 100 cc. of the potassium urate solution were added, followed by 5 cc. of toluol. The flask was fitted with a rubber stopper carrying a 3 inch tube and a bubbling tube reaching nearly to the bottom of the flask. The air, after being filtered through glass wool and 10 per cent sulphuric acid (Némec used sublimate) was led into the flask at a rate of 25 liters per 24 hours. In the control flask, 100 cc. of distilled water were used in lieu of potassium urate solution. The ammonia formed was received in a similar flask containing N/50 sulphuric acid. The temperature was kept constant at 35° C. Four experiments gave concordant results. Table I records the results of one typical experiment together with those of Némec.

These results show no evidence of the presence of any appreciable amount of uricase in soy beans.