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)