Zinc-Alpha-2-Glycoprotein (ZA2G) Human,
Sheep Polyclonal Antibody

Research topic

Energy metabolism and body weight regulation, Oncology

Introduction to the Molecule

Zinc-alpha-2-glycoprotein (ZAG) is found in body fluids such as serum, sweat, and seminal and breast cyst fluids. It is identical in amino acid sequence to tumor-derived lipid mobilizing factor (LMF), a protein associated with the dramatic loss of adipose body stores in cancer cachexia, and has been shown to stimulate lipolysis by adipocytes in vivo and in vitro. A role for ZAG has been proposed in the regulation of body weight, and age-dependent changes in genetically influenced obesity, and also it regulates melanin production by normal and malignant melanocytes. It has also recently been classified as a novel adipokine in that it is produced by both white and brown fat adipocytes and may act in a local autocrine fashion in the reduction of adiposity in cachexia. Controlling ZAG/LMF's activity could be life-saving in the management of certain cancers and other cachexia-inducing conditions, and its possible normal role in body fat store homeostasis is deserving of understanding in its own right. ZAG exhibits a class I major histocompatibility complex (MHC) fold but is a soluble protein rather than being anchored to plasma membranes and does not associate with alpha-2-microglobulin in humans. Like antigen-presenting MHC class I proteins, ZAG has an open apical groove, and X-ray crystallography of human-derived ZAG revealed an unidentifiable electron density in a similar position to that occupied by antigenic peptides in classical MHC proteins and glycolipids in isoforms of CD1. This presumptive ligand is not a peptide, and the groove is too small to hold a glycolipid such as is presented by CD1 isoforms. By analogy with all other MHC class I-related proteins that have an open apical groove [some do not ], occupancy by a ligand is probably crucial to ZAG's biological function. Despite all of the structural and biochemical evidence that ZAG binds a ligand, none has so far been found by extraction from protein isolated from biological fluids. This difficulty could be because the ligand is labile, heterogeneous, or readily lost during purification procedures. Knowing more about how ZAG interacts with the compounds it has been found to bind, both natural and artificial, will inform searches for the elusive ligand(s) and its/their role in ZAG's signaling function.

Note

This product is for research use only.

Source of Antigen

293 cell line (Human embryonic kidney)

Host

Sheep

Preparation

The antibody was raised in sheep by immunization with the recombinant Human ZA2G.

Amino Acid Sequence

Species Reactivity

Human
Not yet tested in other species.

Purification Method

Immunoaffinity chromatography on a column with immobilized recombinant Human ZA2G.

Antibody Content

0.1 mg (determined by BCA method, BSA was used as a standard)

Formulation

The antibody is lyophilized in 0.05 M phosphate buffer, 0.1 M NaCl, pH 7.2. AZIDE FREE.

Reconstitution

Add 0.1 ml of deionized water and let the lyophilized pellet dissolve completely. Slight turbidity may occur after reconstitution, which does not affect activity of the antibody. In this case clarify the solution by centrifugation.

Storage/Stability

The lyophilized antibody remains stable and fully active until the expiry date when stored at –20°C. Aliquot the product after reconstitution to avoid repeated freezing/thawing cycles and store frozen at –80°C. Reconstituted antibody can be stored at 4°C for a limited period of time; it does not show decline in activity after one week at 4°C.

Quality Control Test

Indirect ELISA – to determine titer of the antibody
SDS PAGE – to determine purity of the antibody

Applications

ELISA, Western blotting

References

• Sanchez, L. M., LopezOtin, C., and Bjorkman, P. J. Biochemical characterization and crystalization of human Zn-alpha(2)-glycoprotein, a soluble class I major histocompatibility complex homolog.
• Burmeister, W. P., Gastinel, L. N., Simister, N. E., Blum, M. L., and Bjorkman, P. J. Crystal structure at 2.2 Å resolution of the MHC-related neonatal Fc receptor.
• Sanchez, L. M., Chirino, A. J., and Bjorkman, P. J. Crystal structure of human ZAG, a fat-depleting factor related to MHC molecules.
• Bennett, M. J., Lebron, J. A., and Bjorkman, P. J. Crystal structure of the hereditary haemochromatosis protein HFE complexed with transferrin receptor.
• Im, J. S., Yu, K. O. A., Illarionov, P. A., LeClair, K. P., Storey, J. R., Kennedy, M. W., Besra, G. S., and Porcelli, S. A. Direct measurement of antigen binding properties of CD1 proteins using fluorescent lipid probes.
• Russell, S. T., and Tisdale, M. J. Effect of a tumour-derived lipid-mobilising factor on glucose and lipid metabolism in vivo.
• Gohda, T., Makita, Y., Shike, T., Tanimoto, M., Funabiki, K., Horikoshi, S., and Tomino, Y. Identification of epistatic interaction involved in obesity using the KK/Ta mouse as a type 2 diabetes model-Is Zn-alpha(2) glycoprotein-1 a candidate gene for obesity?.
• Tada, T., Ohkubo, I., Niwa, M., Sasaki, M., Tateyama, H., and Eimoto, T. Immunohistochemical localization of Zn-alpha- 2-glycoprotein in normal human tissues.
• Russell, S. T., Zimmerman, T. P., Domin, B. A., and Tisdale, M. J. Induction of lipolysis in vitro and loss of body fat in vivo by zinc-alpha(2)-glycoprotein.
• Bürgi, W., and Schmid, K. Preparation and properties of Zn-alpha- 2-glycoprotein of normal human plasma.
• Niazi, K. R., Porcelli, S. A., and Modlin, R. L. The CD1b structure: antigen presentation adapts to a high-fat diet.
• Hale, L. P. Zinc alpha-2-glycoprotein regulates melanin production by normal and malignant melanocytes.
• Bao, Y., Bing, C., Hunter, L., Jenkins, J. R., Wabitsch, M., and Trayhurn, P. Zinc-alpha(2)-glycoprotein, a lipid mobilizing factor, and is expressed and secreted by human (SGBS) adipocytes.
• Bing, C., Bao, Y., Jenkins, J., Sanders, P., Manieri, M., Cinti, S., Tisdale, M. J., and Trayhurn, P. Zinc-alpha-2-glycoprotein, a lipid-mobilizing factor, is expressed in adipocytes and upregulated in mice with cancer cachexia.
• Bing, C., Bao, Y., Jenkins, J., Sanders, P., Manieri, M., Cinti, S., Tisdale, M. J., and Trayhurn, P. Zinc-{alpha}2-glycoprotein, a lipid mobilizing factor, is expressed in adipocytes and is up-regulated in mice with cancer cachexia.
• Díez-Itza, I., Sánchez, L. M., Allende, M. T., Vizoso, F., Ruibal, Á., and López-Otín, C. Zn-alpha- 2-glycoprotein levels in breast cancer cytosols and correlation with clinical, histological and biochemical parameters.

By research topic:

• Energy metabolism and body weight regulation
• Oncology

By molecule:

• Zinc-Alpha-2-Glycoprotein