The function of GATD3 (glutamine amidotransferase class 1 domain containing 3, ENSG00000160221) is as follows. Acts as a mitochondrial deglycase involved in the removal of early non-enzymatic glycation adducts from amino acids and nucleotides, thereby restricting the formation of advanced glycation end products (AGEs) within mitochondria (PubMed:35307029). Required to maintain low levels of glycation on mitochondrial ribosomal RNA and proteins, supporting efficient mitochondrial gene expression. Contributes to mitochondrial homeostasis, normal respiratory capacity, and proper mitochondrial network organization. Acts also as a mitochondrial regulator of malate dehydrogenase MDH2 by competitively limiting the association of MDH2 with the mitochondrial deacetylase SIRT3, thereby preserving MDH2 acetylation and enzymatic activity. Through this mechanism, supports efficient conversion of malate to oxaloacetate, sustaining TCA cycle continuity and oxidative phosphorylation (PubMed:39738099). {ECO:0000269|PubMed:35307029, ECO:0000269|PubMed:39738099}.