CD38, also known as ADP-ribosyl cyclase, is a Type II integral membrane protein. The enzyme is able to transform NAD(P)+ into three different products with calcium mobilizing ability; cyclic ADP-ribose, NAADP+ , and ADP-ribose 3 . CD38 is expressed in B and T lymphocytes, osteoclasts, and in cardiac, pancreatic, liver and kidney cells 1, 4 . Through its production of cyclic ADP-ribose, CD38 modulates calcium-mediated signal transduction in many types of cells, including neutrophils and pancreatic b cells 5, 6.
The recombinant human CD38 (rhCD38, ADP-ribosyl cyclase, amino acid residues 43 to 300, P28907) was expressed with an N-terminal signal peptide and a C-terminal 6X His tag in a murine myeloma cell line, NS0.
The purified, secreted rhCD38 has an N-terminal sequence of V43PRWRQQWSG. The 264 amino acid protein predicts a molecular mass of 31 kD and migrates with the apparent molecular mass of approximately 43 kD in SDS-PAGE.
< 1.0 EU per 1 microg of the protein as determined by the LAL method.
Measured by its ability to convert the substrate nicotinamide guanine dinucleotide (NGD +) to cyclic GDP-ribose. The cyclic GDP-ribose is measured by fluorescence at excitation and emission wavelengths of 300 nm and 410 nm, respectively2. The specific activity, measured with 100 microM substrate and 100 ng enzyme in 100 microL of 50 mM MES, pH 6.5, at room temperature is > 2,500 pmoles/min/microg.
Centrifuge the vial before opening to recover entire contents of the vial. Due to possible sublimation during storage, the buffer volume may decrease over time, however, the product is sold by mass and the amount of protein will remain constant. To ensure quantitative recovery, we suggest the stock solution be made in the original vial.
Storage and Stability:
Samples are stable for up to six months at -70 degrees C in a manual defrost freezer after the date of receipt. After receiving, this protein can be aliquoted and stored at above temperature for up to six months without a significant loss of activity. Avoid repeated freeze-thaw cycles.