4beta-carboxy-4alpha-methyl-5alpha-cholesta-8,24-dien-3beta-ol + NAD(+) <=> 3-dehydro-4alpha-methylzymosterol + CO2 + NADH
4beta-carboxy-4alpha-methyl-5alpha-cholesta-8,24-dien-3beta-ol + nad(+) <=> 3-dehydro-4alpha-methylzymosterol + co2 + nadh