Protein Laboratories Rehovot Ltd.
May 2019

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 !!!
Mouse pegylated leptin - Cat no. PEGLEP-1 GENE ID 16846
Description: Mono-pegylated (with 20 kDa PEG)recombinant mouse leptin is an 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 recombinant mouse pegylated leptin runs on the SGS-Page as 48 kDa protein and in gel-filtration on Superdex 200 as over 100 kDa protein. Recombinant mouse pegylated leptin half-life in circulation after SC injection was over 20 hours. Recombinant mouse leptin was purified by proprietary chromatographic techniques according to Salomon et al (2006) Protein Expression and Purification 47, 128–136 and then pegylated. 
Source: Escherichia coli.
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Physical Appearance: White lyophilized (freeze-dried) powder. 
Formulation: The recombinant mouse pegylated leptin was lyophilized from a concentrated (0.65mg/ml) solution with 0.003mM NaHCO3 and the powder contains 35 to 40% protein.

Solubility: It is recommended to reconstitute the lyophilized recombinant mouse pegylated leptin 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 recombinant mouse pegylated leptin although stable at room temperature for several weeks, should be stored desiccated below -20C. Upon reconstitution at > 0.1 recombinant mouse pegylated leptin mg/ml and up to 2 mg/ml and filter sterilization recombinant mouse pegylated leptin 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 of recombinant mouse pegylated leptin addition of a carrier protein (0.1% HSA or BSA) is suggested. Please prevent freeze-thaw cycles. 
Purity: The purity od recombinant mouse pegylated leptin is greater than 99.0% 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 recombinant mouse pegylated leptin could not be determined indicating that the PEG moiety is attached to the N-terminus. 
Dimers and Aggregates: The purified recombinant mouse pegylated leptin consists of > 95% monomers as determined by gel-filtration chromatography.
Biological Activity: PLR’s recombinant mouse pegylated leptin is capable of stimulatng proliferation of BAF/3 cells stably transfected with the long form of human leptin receptor. Its in vitro activity is only slightly lower than the non-pegylated recombinant mouse leptin but in vivo it has profound weight reducing effect (as compared to the non-pegylated recombinant mouse leptin ), resulting mainly from reduced food intake. 
Endotoxin: Less than 0.05 ng/µg (0.5 IEU/µg) of recombinant mouse pegylated leptin . 
Protein content: Protein quantization of recombinant mouse pegylated leptin was carried out by UV spectroscopy at 280 nm using the absorbency value of 0.200 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 recombinant mouse pegylated leptin 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 
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