Protein Laboratories Rehovot Ltd.
December 2018

Certificate of Analysis & Data Sheet

We are the ONLY company producing leptin antagonists and leptins of farm animals including several fish species.

Pegylated human, mouse, rat and ovine leptins and corresponding leptin antagonists are now available!!!

PLR provides a novel service of pegylation of either existing, or provided or custom-made proteins. All PLR's proteins are carrier free (cf) and can be sold in any requested amount !!!
Chicken leptin - Cat no. LEP-2
Description: Recombinant chicken leptin is an one polypeptide chain containing 145 amino and additional Ala at N-terminus acids and having a molecular mass of ~ 16 kDa. Chicken leptin was prepared according to the sequence published by the groups of Taouis and McMutry, purified by proprietary chromatographic techniques, see Raver et al. Protein Expr Purif. 1998 Dec; 14(3):403-8.  
Source: E. coli 
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Physical Appearance: White lyophilized (freeze-dried) powder. 
Formulation: The recombinant protein was lyophilized from a concentrated (1mg/ml) solution with 0.0045mM NaHCO3.
Solubility: It is recommended to reconstitute the lyophilized recombinant chicken leptin in sterile water or 0.4% NaHCO3 adjusted tp pH 8-9, not less than 100µg/ml, which can then be further diluted to other aqueous solutions. 
Stability: Lyophilized recombinant chicken leptin although stable at room temperature for several weeks, should be stored desiccated below -18 C. Upon reconstitution of recombinant chicken leptin at > 0.1 mg/ml and up to 2 mg/ml and filter sterilization chicken leptin can be stored at +4C. 
Purity: Recombinant chicken leptin purity was greater than 98.0% as determined by:
(a) Gel filtration analysis.
(b) Analysis by reducing and non-reducing SDS-PAGE gel. 
Amino Acid Sequence: The sequence of the first five N-terminal amino acids of recombinant chicken leptin was determined and was found to be Ala-Val-Pro-Cys-Gln 
Dimers and Aggregates: The purified recombinant chicken leptin (16K) consists of > 95% monomers as determined by gel-filtration chromatography.
Biological Activity: PLR’s recombinant chicken leptin is biologically active as evidenced by inducing proliferation of BAF/3 cells stably transfected with the long form of human leptin receptor. Its activity is however 5-10 fold lower as compared to mammalian leptins. 
Endotoxin: The endotoxin content of recombinant chicken leptin is less than 0.1 ng/µg (IEU/µg) of chicken leptin  
Protein content: Protein quantitation of recombinant chicken leptin was carried out by UV spectroscopy at 280 nm using the absorbency value of 0.21 as the extinction coefficient for a 0.1% (1mg/ml) solution at pH 8.0. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics). 
Usage: Recombinant chicken leptin is offered by PLR for laboratory research 
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