Urease - Manual

Source:
Jack Bean (Canavalis ensiformis)
CAS:
9002-13-5
EC:
3.5.1.5

Urease catalyzes the hydrolysis of urea:

formula

Jespersen (1975) reports that ammonium carbamate is produced in citrate and Tris buffer.

Urease occurs in many bacteria, several species of yeast and a number of higher plants. Varner (1960) has reviewed it. Two of the best sources are: Jack beans (Canavlia ensiformis) from which it has been crystallized and thoroughly studied, and Bacillus pasteurii.

The enzyme is important in assaying for urea. See Guilbault and Montalvo (1970). Its immobilization has been reported: et al. (1974), James and Pring (1975), Messing (1974), Nakamoto et al. (1975), Sundaram (1973) and Tran-Minh and Broun (1975).

Characteristics of Urease from Jack Bean:

Km: 1.3mM in Tris⋅HCl (Cesareo and Langton, 1992).

Specificity

Urease is specific for urea and hydroxyurea (Fishbein and Carbone 1965). See also Sundaram and Laidler (1970).

Composition

Monomeric (a)urease can polymerize to form six unit polymers of about three million daltons. (Fishbein et al. 1970; Fishbein and Nagarajan 1972a). Andrews and Reithel (1970) report on the sulfhydryl groups. Contaxis and Reithel (1971) indicate the molecule can be split in half with no loss of activity. See also Contaxis and Reithel (1972), Fishbein and Nagarajan (1972b), Lynn (1970), and Bailey and Boulter (1969).

Characteristics of Urease
Molecular Weight

480,000 (Fishbein et al. 1970).

Optimal pH

7.4 (Cesareo and Langton, 1992).

Inhibitors

Heavy metals. NH4+ ions formed. See also Fishbein and Carbone (1965). Sodium and potassium ions are inhibitors (Cesareo and Langton, 1992).

Stabilizers

EDTA in concentrations of 1 X 10-3 M. 50% glycerol solutions protect urease crystalline suspension for several months at 4°C.

 

Urease Products

Description
Activity
Code
Cat. #
Price
Size
Description
Urease
Source:
Jack Bean (Canavalis ensiformis)
A soluble, lyophilized preparation. Tested for ammonia.
Store at -20°C.
Ice Pack required
Activity
≥45 units per mg dry weight
Code
URC
Cat. #
LS003885