Abstract
In alkane-utilizing yeasts, fatty acids derived from alkanes are degraded by the β-oxidation system located in peroxisome with concomitant reduction of NAD to NADH. This indicates that re-oxidation of NADH to NAD is necessary for the continuous operation of β-oxidation in the organelles. Of various NAD-linked enzymes tested, NAD-linked glycerol-3-phosphate dehydrogenase (NAD-G3PDH) was found to be localized in the peroxisomes of alkane-grown Candida tropicalis. In the meantime, FAD-linked glycerol-3-phosphate dehydrogenase (FAD-G3PDH) was located exclusively in the mitochondria of the yeast. These results, together with the inducible nature of NAD-G3PDH with alkanes, strongly suggested the operation of "glycerophosphate shuttle (NAD-G3PDH/FAD-G3PDH)" between the peroxisomes and mitochondria for the transport of reducing equivalents produced in the peroxisomes.
