• Species Reactivity

  Human, Mouse

• Specificity

  Detects human and mouse Proinsulin in direct ELISAs. In direct ELISAs, no cross-reactivity with mature Insulin is observed.

• Source

  Monoclonal Mouse IgG    _2A Clone # 253627

• Purification

  Protein A or G purified from hybridoma culture supernatant

• Immunogen

  E. coli-derived recombinant human Proinsulin    
  Phe25-Asn110    
  Accession # P01308

• Formulation

  Lyophilized from a 0.2 μm filtered solution in PBS with BSA as a carrier protein.

• Label

  Biotin

Applications

• Recommended    
  Concentration

  Sample

• Immunocytochemistry

  8-25 µg/mL

  See below

• 
  

• Intracellular Staining by Flow Cytometry

  2.5 µg/10    ⁶ cells

  beta TC‑6 mouse beta cell insulinoma cell line fixed with paraformaldehyde and permeabilized with saponin

• 
  

Please Note: Optimal dilutions should be determined by each laboratory for each application.  are available in the Technical Information section on our website.

Data Examples

Preparation and Storage

• Reconstitution

  Reconstitute at 0.5 mg/mL in sterile PBS.

• Shipping

  The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.

• Stability & Storage

  Use a manual defrost freezer and avoid repeated freeze-thaw cycles.    

• 12 months from date of receipt, -20 to -70 °C as supplied.

• 1 month, 2 to 8 °C under sterile conditions after reconstitution.

• 6 months, -20 to -70 °C under sterile conditions after reconstitution.

Background: Proinsulin

Proinsulin is synthesized as a single chain, 110 amino acid (aa) preproprecursor that contains a 24 aa signal sequence and an 86 aa proinsulin propeptide. Following removal of the signal peptide, the proinsulin peptide undergoes further proteolysis to generate mature insulin, a 51 aa disulfide-linked dimer that consists of a 30 aa B chain (aa 25‑54) bound to a 21 aa A chain (aa 90‑110). The 34 aa intervening peptide (aa 55‑89) that connects the B and A chains is termed the C-peptide. Human proinsulin shares 84% and 80% aa sequence identity with rat and bovine proinsulin, respectively. Most of the sequence variation between species occurs in the region of the C‑peptide (1). This peptide generates a structural conformation that allows for the correct formation of the intrachain disulphide bonds (1). Insulin is a molecule that facilitates the cellular uptake of glucose. This is accomplished by regulating the appearance of membrane glucose transporters. Low insulin levels or lack of insulin are associated with type 2 and type 1 diabetes mellitus, respectively. These conditions are associated with an increased risk for microvascular complications such as retinopathy, nephropathy, and peripheral neuropathy (3). Proinsulin also circulates, but its physiologic role is less well understood. It does possess about 25% of the activity of mature insulin, but it would seem unlikely to be a natural substitute for insulin (4). In type 2 diabetes, an elevated proinsulin to insulin ratio in the circulation is a well-known abnormality (5‑9). Perhaps this abnormality represents either compromised proteolytic processing or a general inability to process increased levels of insulin precursor (5). In any event, proinsulin will stimulate amylin secretion by beta ‑cells, and amyloid formation in pancreatic islets that promotes decreased beta cell function (10). Studies also suggest that fasting serum proinsulin may be a better predictor of future type 2 diabetes than fasting insulin levels in obese children (11).

• References:

1. Bell, G.I. et al. (1980) Nature 284:26.

2. Barbetti, F. et al. (1990) J. Clin. Endocrinol. Metab. 71:164.

3. Forst, T. et al. (2008) Exp. Diabetes Res. 2008:176245.

4. Steffes, M.W. et al. (2003) Diabetes Care 26:832.

5. Roder, M.E. et al. (1999) Diabetes Care 22:609.

6. Porte, D. Jr. (1991) Diabetes 40:166.

7. Gordon, P. et al. (1974) Diabetologia 34:483.

8. Saad, M.F. et al. (1990) J. Clin. Endocrinol. Metab. 70:1247.

9. Roder, M.E. et al. (1995) J. Clin. Endocrinol. Metab. 80:2359.

10. Dworacka, M. et al. (2006) Int. J. Clin. Pharmacol. Ther. 44:14.

11. Kamoda, T. et al. (2006) Diabetes Obes. Metab. 8:192.

• Entrez Gene IDs:

  3630 (Human); 16333 (Mouse)

• Alternate Names:

  IDDM2; ILPR; insulin; IRDN; MODY10; Proinsulin