The abundance of glyceraldehyde-3-phosphate dehydrogenase in eukaryotic cells is relatively unaffected by eternal factors. In western blot analysis the level of GAPDH; a 38kDa protein; can be used as a reference value for loading control. Has both glyceraldehyde-3-phosphate dehydrogenase and nitrosylase activities; thereby playing a role in glycolysis and nuclear functions; respectively. Participates in nuclear events including transcription; RNA transport; DNA replication and apoptosis. Nuclear functions are probably due to the nitrosylase activity that mediates cysteine S-nitrosylation of nuclear target proteins such as SIRT1; HDAC2 and PRKDC By similarity. Glyceraldehyde-3-phosphate dehydrogenase is a key enzyme in glycolysis that catalyzes the first step of the pathway by converting D-glyceraldehyde 3-phosphate (G3P) into 3-phospho-D-glyceroyl phosphate.