The mitochondrial D-lactate dehydrogenase is a stereoselective dehydrogenase that targets a wide variety of D-2- hydroxyacids, particularly those with small to moderately sized hydrophobic groups attached to the C2 atom. It includes D-lactate which is generated in small amounts either endogenously through the methylglyoxal metabolism pathway or exogenously via intestinal bacterial activity and dietary intake. The dehydrogenase acts specifically on D-lactate, not on its stereoisomer L-lactate, and prevents the toxic accumulation of D-lactate in the organism (PubMed:30931947, PubMed:38373542). By converting branched-chain D-2- hydroxyacids into branched-chain ketoacids, it may indirectly regulate branched-chain amino acid metabolism (By similarity). {ECO:0000250|UniProtKB:Q7TNG8, ECO:0000269|PubMed:30931947, ECO:0000269|PubMed:38373542}. This is the function of LDHD (lactate dehydrogenase D, ENSG00000166816).