The Molecular Weight of Urease

While urease was the first enzyme to be isolated, its molecular weight has not been determined thus far, although molecular weight determinations have been made with pepsin (1, 2) and the yellow respiratory enzyme (3) and recently with catalase (4-6). We considered it of interest to be able to compare the size of the urease molecule with that of other enzymes, as well as with other proteins in general. It also interested us to compare the molecular weights of the four crystallizable jack bean proteins, namely urease, canavalin, concanavalin A, and concanavalin B. Finally, it is hoped that at some later date knowledge of the molecular weights of enzymes may be of value when attempts are made to explain the mechanism of enzyme action.