Omentin Human E. coli

Introduction to the Molecule

Omentin (intelectin-1, intestinal lactoferin receptor, endothelian lectin HL-1, galactofurano­sebinding lectin) is newly identified secretory protein that is highly and selectively expressed in visceral adipose tissue relative to subcutaneous adipose tissue (adipokine). The mature omentin is secretory glycoprotein consisting of 295 amino acids and 1-linked oligosacharides, and its basic structural unit is a 120-kDa homotrimer in which 40-kDa polipeptides are bridged by disulfide bonds. Omentin has been identified in other tissue at lower expression levels such are Paneth cells, endothelial cells, and visceral adipose stromal-vascular cells. A homolog of omentin has been identified that shares 83% amino acid identity with omentin and was referred to as omentin 2. The two omentin genes, omentin 1 and omentin 2, are localized adjacent to each other in chromosomal region, which has been previously linked to type 2 diabetes in several populations. To determine the impact of obesity-dependent insulin resistance on the regulation of two omentin isoforms, gene expression and plasma levels were measured in lean, overweight, and obese subjects. Omentin-1 was shown to be the major circulating isoform in human plasma. Lean subjects had significantly higher omentin-1 plasma levels than obese and overweight subjects. In addition, higher plasma omentin-1 levels were detected in women compared with men. Plasma omentin-1 levels were inversely correlated with BMI, waist circumference, leptin levels, and insulin resistance as measured by homeostasis model assessment and positively correlated with adiponectin and HDL levels. In summary, decreased omentin-1 levels are associated with increasing obesity and insulin resistance. An independent experiment reported that the addition of recombinant omentin-1 in vitro did not affect basal glucose uptake but did enhance insulin-stimulated glucose uptake in both subcutaneous and omental human adipocytes. Omentin-1 increased Akt phosphorylation in the absence and presence of insulin and may regulate insulin action. A recent study of women with the polycystic ovary syndrome (PCOS) found significantly reduced omentin-1 mRNA expression and protein levels in adipose tissue in overweight PCOS women. In addition, significantly lower plasma omentin-1 levels were detected in these women.

Research topic

Diabetology - Other Relevant Products, Energy metabolism and body weight regulation, Reproduction

Description

Total 294 AA. MW: 32.7 kDa (calculated). N-terminal His-tag, 14 extra AA (highlighted). The AA sequence is identical to UniProtKB/Swiss-Prot entry Q8WWA0 (AA19–298).

Amino Acid Sequence

Source

E. coli

SDS-PAGE gel

12% SDS-PAGE separation of Human Omentin 1. M.W. marker – 14, 21, 31, 45, 66, 97 kDa 2. reduced and heated sample, 5μg/lane 3. non-reduced and non-heated sample, 5μg/lane

Formulation

Filtered (0,4 μm) and lyophilized in 0.5 mg/mL in 20 mM Tris, 50mM NaCl , pH 8.0

Reconstitution

Add deionized water to prepare a working stock solution of approximately 0.5 mg/mL and let the lyophilized pellet dissolve completely. Product is not sterile! Please filter the product by an appropriate sterile filter before using it in the cell culture.

Storage, Stability/Shelf Life

Store lyophilized protein at –20°C. Lyophilized protein remains stable until the expiry date when stored at –20°C. Aliquot reconstituted protein to avoid repeated freezing/thawing cycles and store at –80°C for long term storage. Reconstituted protein can be stored at 4°C for a limited period of time; it does not show any change after one week at 4°C.

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Quality Control Test

BCA to determine quantity of the protein.

SDS PAGE to determine purity of the protein.

Applications

Western blotting

Note

This product is intended for research use only.

References to this Product

• Yamawaki H, Tsubaki N, Mukohda M, Okada M, Hara Y. Omentin, a novel adipokine, induces vasodilation in rat isolated blood vessels. Biochem Biophys Res Commun. 2010 Mar 19;393 (4):668-72

References

• de Souza Batista CM, Yang RZ, Lee MJ, Glynn NM, Pray J, Yu DZ, Ndubuizu K, Patil S, Schwartz A, Kligman M, Fried SK, Gong DW, Shuldiner AR, Pollin TI, McLenithan JC. Omentin plasma levels and gene expression are decreased in obesity. Diabetes. 2007 Jun;56 (6):1655-61
• Furst A, Schaffler A, Buchler C, Scholmerich J, Herfarth H, Neumeier M. Genomic structure of human omentin, a new adipocytokine expressed in omental adipose tissue. Biochim Biophys Acta. 2005 Dec 30;1732 (1-3):96-102
• Hara Y, Okada M, Mukohda M, Tsubaki N, Yamawaki H. Omentin, a novel adipokine, induces vasodilation in rat isolated blood vessels. Biochem Biophys Res Commun. 2010 Mar 19;393 (4):668-72
• Li Q, Guo L, Pan HY. Changes of serum omentin-1 levels in normal subjects and in patients with impaired glucose regulation and with newly diagnosed and untreated type 2 diabetes. Diabetes Res Clin Pract. 2010 Apr;88 (1):29-33
• Moreno-Navarrete JM, Catalan V, Ortega F, Gomez-Ambrosi J, Ricart W, Fruhbeck G, Fernandez-Real JM. Circulating omentin concentration increases after weight loss. Nutr Metab (Lond). 2010;7:27
• Randeva HS, Lewandowski KC, Lehnert H, Farhatullah S, O'Hare P, Tan BK, Adya R. Omentin-1, a novel adipokine, is decreased in overweight insulin-resistant women with polycystic ovary syndrome: ex vivo and in vivo regulation of omentin-1 by insulin and glucose. Diabetes. 2008 Apr;57 (4):801-8
• Tan BK, Adya R, Farhatullah S, O'Hare P, Lewandowski KC, Lehnert H, Randeva HS. Omentin-1, a novel adipokine, is decreased in overweight insulin-resistant women with polycystic ovary syndrome: ex vivo and in vivo regulation of omentin-1 by insulin and glucose. Diabetes. 2008 Apr;57 (4):801-8
• Wu HB, Hansen BC, Hu H, Shuldiner AR, Fried SK, Lee MJ, McLenithan JC, Gong DW, Yang RZ, Pray J. Identification of omentin as a novel depot-specific adipokine in human adipose tissue: possible role in modulating insulin action. Am J Physiol Endocrinol Metab. 2006 Jun;290 (6):E1253-61
• Wurm S, Neumeier M, Weigert J, Schaffler A, Buechler C. Plasma levels of leptin, omentin, collagenous repeat-containing sequence of 26-kDa protein (CORS-26) and adiponectin before and after oral glucose uptake in slim adults. Cardiovasc Diabetol. 2007;6:7
• Yilmaz Y, Yonal O, Kurt R, Alahdab YO, Eren F, Ozdogan O, Celikel CA, Imeryuz N, Kalayci C, Avsar E. Serum levels of omentin, chemerin and adipsin in patients with biopsy-proven nonalcoholic fatty liver disease. Scand J Gastroenterol. 2011 Jan;46 (1):91-7

By research topic:

• Diabetology - Other Relevant Products
• Energy metabolism and body weight regulation
• Reproduction

By molecule:

• Omentin-1