. Among all metals tested (Cu2+, Ni2+, Co2+, Mn2+, Zn2+) only Cu2+ and Ni2+ can exert an inhibitory effect on catalysis. 2. The effect of divalent cations (copper and nickel) on alcohol dehydrogenase 1 (ADH1) from Kluyveromyces marxianus is a mixed type inhibition. 3. The ionization constants of the oxidative and reductive reaction indicate that the interaction of metals with both enzyme-cofactor (ECI) and enzyme-cofactor-substrate (ECIS) produces a light effect base-strengthening on the acid ionizing groups but displays a stronger effect acid-strengthening (almost 2 pH U for the oxidative reaction and almost 0.5 pH U for the reductive reaction) on the basic ionizing groups of the enzyme-cofactor complex. 4. The metals can also decrease the ampholytic nature of the catalytic site (from almost 2.5 U to almost 0.5 pH U for the oxidative reaction).
METAL-ENZYME INTERACTIONS IN ADH 1 FROM KLUYVEROMYCES MARXIANUS.
GASTALDI, Daniela;PESSIONE, Enrica;GIUNTA, Carlo
1993-01-01
Abstract
. Among all metals tested (Cu2+, Ni2+, Co2+, Mn2+, Zn2+) only Cu2+ and Ni2+ can exert an inhibitory effect on catalysis. 2. The effect of divalent cations (copper and nickel) on alcohol dehydrogenase 1 (ADH1) from Kluyveromyces marxianus is a mixed type inhibition. 3. The ionization constants of the oxidative and reductive reaction indicate that the interaction of metals with both enzyme-cofactor (ECI) and enzyme-cofactor-substrate (ECIS) produces a light effect base-strengthening on the acid ionizing groups but displays a stronger effect acid-strengthening (almost 2 pH U for the oxidative reaction and almost 0.5 pH U for the reductive reaction) on the basic ionizing groups of the enzyme-cofactor complex. 4. The metals can also decrease the ampholytic nature of the catalytic site (from almost 2.5 U to almost 0.5 pH U for the oxidative reaction).
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