 The protein encoded by this gene is included in class IV of the sirtuin family.SIRT4 is a mitochondrial ADP-ribosyltransferase that inhibits mitochondrial glutamate dehydrogenase 1 activity, thereby downregulating insulin secretion in response to amino acids.It has been shown that SIRT4 regulates fatty acid oxidation and mitochondrial gene expression in liver and muscle cells.