Urease present in soybean seed is known to consist of two isozyme variants. These variants are referred to as electrophoretically fast or slow on polyacrylamide gels and are believed to be polymers of a single subunit (Buttery and Buzzell, 1971; Polacco and Havir, 1979). The slow variant, considered a hexamer, has been estimated at 480,000 daltons by Polacco and Havir (1979) and at 520,000 daltons by Buttery and Buzzell (1971).
Mervosh, T. L. and Hymowitz, T.
"Research Notes : United States : Screening of the USDA soybean cultivar collection for slow and fast urease isozymes,"
Soybean Genetics Newsletter: Vol. 14
, Article 63.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol14/iss1/63