Comparative oxidation of 2-propyn-1-ol with other low molecular weight unsaturated and saturated primary alcohols by bovine liver catalase in vitro.

The oxidative metabolism of low molecular weight, saturated and unsaturated, primary alcohols, which include ethanol, allyl alcohol (2-propen-1-ol), and propargyl alcohol (2-propyn-1-ol), is generally accepted to occur via alcohol dehydrogenase; however, compared to other short-chain alcohols, 2-propyn-1-ol is a poor substrate for this enzyme. Accordingly, we have examined liver catalase as an alternative pathway for the oxidation or bioactivation of 2-propyn-1-ol to 2-propyn-1-al, a highly reactive alpha,beta-unsaturated aldehyde. The rates of oxidation for a series of low molecular weight, saturated, primary alcohols and selected unsaturated alcohols were determined for the bovine liver catalase-catalyzed reaction by measuring aldehyde production over time employing a GC procedure. A negative correlation was found for log rates of oxidation versus molecular size (volume) of the substrates (p < 0.01); however, the rate of oxidation for 2-propyn-1-ol was higher than predicted by this relation and was 30% greater than the oxidation rate determined for ethanol. In addition, 2-propyn-1-ol-derived 2-propyn-1-al inhibited the peroxidatic and catalytic activities of catalase, whereas 2-propen-1-ol-derived 2-propen-1-al had no effect on these activities of catalase. Inhibition was blocked by GSH; and the activity was not restored to the inhibited enzyme by GSH treatment or dialysis.(ABSTRACT TRUNCATED AT 250 WORDS)