Mucin 16, Recombinant, Human (MUC16, MUC-16, CA125, CA-125, CA125 Ovarian Cancer Antigen, Cancer Ant

MUC16, also known as the CA125 antigen, is a mucin protein that may be found in type I transmembrane or secreted forms that are used monitor the progress of epithelial ovarian cancer therapy. Expression of isoforms, proteolytic cleavage, and heavy N- and O- linked glycosylation produce forms of human MUC16 that can vary from 1148-22152aa in length and 200-5000kD in size. The 22152aa form contains ser/thr-rich N-terminal tandem repeats, 4 LRR (Leu-rich repeat) domains, 56 SEA (sea urchin sperm protein, enterokinase and agrin) domains, a transmembrane domain, and a 31aa cytoplasmic domain that includes a tyrosine phosphorylation site. SEA domains are ~120aa in length, contain conserved residues including potential O-glycosylation sites and a pair of cysteines, and are of ten found in transmembrane mucins. The protein represents aa21102-21992 of the full sequence and includes the last 6 SEA domains. It shares 68% aa identity with canine MUC16. MUC16 is overexpressed by tumor cells including ovarian and mesothelial cancers. The transmembrane form can adhere to mesothelinin the peritoneum, facilitating metastasis of ovarian cancer to the peritoneal cavity. MUC16 also binds galectin-1 on immune cells and enhances its expression on tumor cells. MUC16-expressing tumors adhere to NK cells, downregulate CD16 and suppress NK response, which may promote immune evasion. MUC16 is also cyclically expressed in the endometrium and may contribute to immune privilege during pregnancy. In the eye, MUC16 and other mucins protect the cornea and keep it hydrated. It is altered on the conjunctival epithelium of patients with non-Sjogren dry eye syndrome. Human Mucin 16 (Met21005-Gln21992 (His21384Pro, Ser21487Cys, & Leu21691Pro) with a C-terminal 6-His tag, expressed in Chinese hamster ovary (CHO) cells (Q8WXI7) , SDS-PAGE: 170-200kD, reducing conditions. Biological Activity: Measured by its binding ability in a functional ELISA. When recombinant human MUC-16 is coated at 1ug/ml (100ul/well), the concentration of recombinant human Galectin-3 that produces 50% of the optimal binding response is found to be ~0.35-1.4ug/ml. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 6 months after receipt at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.