Operational stability of enzymes. Acylase-catalyzed resolution of N-acetyl amino acids to enantiomerically pure L-amino acids.
The method of measuring enzyme deactivation by monitoring necessary addition of fresh enzyme to keep a constant degree of conversion in a CSTR at constant [E] x tau, the product of concentration of active enzyme [E] and residence time tau, was successfully applied to acylase I from porcine kidney and Aspergillus oryzae fungus. Fungal enzyme was found to be more stable than kidney enzyme. Activation by both Co2+ and Zn2+ ions also yielded increased operational enzyme stability: Co2+ and Zn2+ are better stabilizers than activators. Mg2+ and Ca2+ are found to be neither activators nor stabilizers. Fungal acylase partially deactivated by exposition to a metal-free medium in the CSTR was reactivated by addition of Zn2+, demonstrating that loss of Zn2+ from the enzyme molecule is mainly responsible for deactivation in a continuous reactor.
Bommarius
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Degussa AG, Organic and Biological Chemistry R&D, Hanau, Germany.
Drauz
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Klenk
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Wandrey
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D000581:Amidohydrolases / Q000737:chemistry* / Q000378:metabolism; D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification*; D000818:Animals; D001236:Aspergillus oryzae / Q000201:enzymology; D002413:Cations, Divalent; D004789:Enzyme Activation; D007668:Kidney / Q000201:enzymology; D011489:Protein Denaturation; D013237:Stereoisomerism; D013552:Swine
D000596:Amino Acids; D002413:Cations, Divalent; D000581:Amidohydrolases; C019665:amidase