Purification and general properties of argininosuccinate lyase from jack bean, Canavalia ensiformis (L.)DC.
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ABSTRACT: 1. Argininosuccinate lyase (EC 4.3.2.1) from jack bean [Canavalia ensiformis (L.) DC] seeds was purified 532-fold from an acetone-butanol-dried powder. 2. The enzyme functions reversibly and exhibits maximum stability at 16 degrees . 3. At 16 degrees it has a half-life (t((1/2))) of 263min. 4. The enzyme is both cold-labile (t((1/2)) 131min. at 0 degrees ) and heat-inactivated (t((1/2)) 74min. at 38 degrees ); inactivation appears to be irreversible. 5. Treatment of the acetone-butanol-extracted powder with sodium dodecyl sulphate increased the sensitivity of the enzyme to temperature (t((1/2)) 70min. at 0 degrees ; t((1/2)) 23min. at 38 degrees ). 6. Addition, to the purified enzyme, of a fraction containing lipid from the seed increased the half-life to about 510min. at either 0 degrees or 38 degrees . 7. Arginine or homoarginine, and to a smaller extent some other amino acids or fumarate, protected the enzyme from cold-inactivation. 8. Reactivation attempts with both the cold- and heat-inactivated enzyme failed. 9. The K(m) value for argininosuccinate at pH7.5 is 1.3x10(-4). 10. The enzyme was inactivated completely within 15min. at 16 degrees by 0.5mm-p-hydroxymercuribenzoate, and subsequent exposure to 5mm-cysteine had no restorative effect.
SUBMITTER: Rosenthal GA
PROVIDER: S-EPMC1187728 | biostudies-other | 1969 May
REPOSITORIES: biostudies-other
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