Protein Laboratories Rehovot Ltd.
March 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 !!!
Human pegylated super leptin antagonist (mutant D23L/L39A/D40A/F41A) - Cat no. PESLAN-2
Description: Mono-pegylated (with 20 kDa PEG) recombinant super human leptin antagonist is one polypeptide chain containing 146 amino, an additional Ala at N-terminus and one molecule of PEG 20 kDa at its N-terminus, having an expected molecular mass of ~ 35.6 kDa as determined by MS. However due to enlarged hydrodymanic volume human pegylated leptin antagonist runs on the SGS-Page as 48 kDa protein and in gel-filtration on Superdex 200 as over 200 kDa protein. Its half-life in circulation after SC injection was over 20 hours. Super human leptin antagonist (SHLA) was initially mutated, resulting in D23L/L39A/D40A/F41A mutant that was purified by proprietary chromatographic techniques. Pegylation of human leptin antagonist similar to that described in Elinav et al. Endocrinology 150:3083-91 (2009) for PEG-MLA. More details can be found in Shpilman at al., J. Biol. Chem. 286:4439-42 (2011). 
Source: Escherichia coli.
Lot Number:  
Quantity Shipped:  
Physical Appearance: White lyophilized (freeze-dried) powder. 
Formulation: The human pegylated leptin antagonist was lyophilized from a concentrated (0.65mg/ml) solution with 0.003mM NaHCO3.
Solubility: It is recommended to reconstitute the lyophilized human pegylated leptin antagonist in sterile water or sterile 0.4% NaHCO3 adjusted to pH 8-9, not less than 100µg/ml, which can then be further diluted with other aqueous solutions. 
Stability: Lyophilized human pegylated leptin antagonist although stable at room temperature for several weeks, should be stored desiccated below - 20C. Upon reconstitution at > 0.1 mg/ml and up to 2 mg/ml of human pegylated leptin antagonist and filter sterilization human pegylated leptin antagonist can be stored at 4C or even room temperature for several weeks making it suitable for long term infusion studies using osmotic pumps. At lower concentration addition of a carrier protein (0.1% HSA or BSA) is suggested. Please prevent freeze-thaw cycles. 
Purity: The purity of human pegylated leptin antagonist is 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 N-terminal amino acids of human pegylated leptin antagonist could not be determined indicating that the PEG moiety is attached to the N-terminus. 
Dimers and Aggregates: The purified human pegylated leptin antagonist consists of > 90% monomers as determined by gel-filtration chromatography.
Biological Activity: PLR’s human pegylated leptin antagonist is capable of inhibiting leptin-induced proliferation of BAF/3 cells stably transfected with the long form of human leptin receptor. Its in vitro activity is 6-8 fold lower than the non-pegylated human leptin antagonist but in vivo it has profound weight gain effect (as compared to the non-pegylated human leptin antagonist), resulting mainly from increased food intake. The in vivo activity of human pegylated super leptin antagonist was compared to that of human pegylated leptin antagonist is 9-27 fold higher. 
Endotoxin: Less than 0.01 ng/µg (0.1 EU/µg of protein) of human pegylated leptin antagonist  
Protein content: Protein quantization of human pegylated leptin antagonist was carried out by UV spectroscopy at 280 nm using the absorbency value of 0.880 as the extinction coefficient for a 0.1% (1mg/ml) protein solution at pH 8.0. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).  
Usage: PLR's human pegylated leptin antagonist is furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals. It is for Research Purposes Only. Commercial Use has been Licensed Exclusively to a Third Party. 
Date Shipped: 23.09.2010