thus serves to break down glucose for energy and carbon molecules. In addition to this long established metabolic function, GAPDH has recently been implicated in several non-metabolic processes, including transcription activation, initiation of apoptosis,[1] ER to Golgi vesicle shuttling, and fast axonal, or axoplasmic transport.[2] In sperm, a testis-specific isoenzyme GAPDHS is expressed.