The Non-Identity of Jack Bean Agglutinin with Crystalline Urease

Abstract Hotchkiss and Tauber (1) have stated that crystalline urease agglutinates washed rabbit and mouse erythrocytes, but not those of sheep. As little as 0.00014 mgm. of urease is said to have caused a perceptible effect. This work is quite erroneous. We find that washed rabbit and dog erythrocytes are not agglutinated in the slightest when incubated for two hours at 37°C. with as much as 3 mgm. of recrystallized urease. It is true that the jack bean, like many other beans, contains a substance which agglutinates red cells. This is thermolabile and non-dialyzable. We have obtained it in solution in such concentration that 1 cc. will cause an almost complete agglutination of 5 cc. of 2 per cent erythrocyte suspension in five minutes at room temperature. Diluted 100 times the material will produce an agglutination detectable by microscope within thirty minutes at 37°C. This 100-fold diluted solution contained only about 0.00015 mgm. of urease per cubic centimeter. The addition of large quantities of crystalline urease to the agglutinin solution does not retard its action. The agglutinin solution was prepared by washing 50 grams of jack bean meal on a filter funnel successively with 500-cc. portions of 95 per cent alcohol, 40 per cent alcohol, 30 per cent alcohol, 20 per cent alcohol, and distilled water. The residue was stirred up with 200 cc. of 1 per cent neutral phosphate and filtered by gravity, giving a filtrate rich in agglutinin.