SPARC

Programmed cell death via apoptosis is a key controlled physiological process instigated by the cell death receptor family, their ligands, and the caspase cysteine protease family. All caspases exist in a precursor form that contains a prodomain, and large and small catalytic subunits. A cleavage event adjacent to an aspartate liberates one large and one small subunit, which are now free to associate into an active a2b2 tetramer. Caspases are activated by triggers such as ligand-receptor interactions, growth factor deprivation, and cell function inhibitors.

GAPDH is a 146kD tetramer glycolytic pathway metabolic enzyme composed of four 30-40 kDa subunits. It is responsible for reversibly phosphorylating its substrate glyceraldehyde 3-phosphate within the glycolytic pathway.  Apart from its role in glycolysis, GAPDH may have other roles such as transcriptional activation. Due to its housekeeping role, GAPDH is highly expressed in almost all tissues, allowing its use as an internal loading control (traditionally for mRNA expression comparisons, but also in protein studies.

GAPDH is a 146 kD tetramer glycolytic pathway metabolic enzyme responsible for reversibly phosphorylating glyceraldehyde 3-phosphate. It may have other possible functions in transcriptional activation. GAPDH is highly expressed due to this housekeeping role, and its prevalent expression has allowed its use as an internal loading control – traditionally for mRNA expression comparisons – but also in protein studies.

Cell death via apoptosis is a fundamental cellular function triggered by the cell death receptor family and their ligands which signal through downstream adaptor molecules and the caspase protease family. All caspases exist in a precursor form composed of a prodomain, and large and small catalytic subunits. Caspases require a cleavage adjacent to an aspartate to liberate one large and one small subunit, which can then associate into an a2b2 tetramer.