Certificate of Analysis & Data Sheet
Prolactin is a pituitary hormone involved in the stimulation of milk production, salt and water regulation, growth, development and reproduction. The initial step in its action is the binding to a specific membrane receptor (prolactin receptor) which belongs to the superfamily of class 1 cytokine receptors. Prolactin (PRL) is a hormone involved in a variety of important functions including ion transport and osmoregulation, stimulation of milk, protein synthesis as well as the regulation of numerous reproductive functions. PRL exerts its influence on different cell types through a signal transduction pathway which begins with the binding of the hormone to a transmembrane PRL receptor. PRL receptor, varies in size (short and long forms) with tissue source and species, from ~40 kDa to 100 kDa. The PRL receptor consists of at least three separate domains: an extracellular region with 5 cysteines which contains the prolactin binding site, a single transmembrane domain and a cytoplasmic region, the length of which appears to influence ligand binding and regulate cellular function. Recombinant rabbit Prolactin Receptor Extra Cellular Domain (rbPRLR-ECD) produced in E.Coli is a non-glycosylated, polypeptide chain containing 207 amino acids and having a molecular mass of 23806 Da was prepared according to Bignon et al. (1994) JBC 269; 3318-24 and tested according to Gertler et al. (1996) JBC 271; 24482-91.
Filtered White lyophilized (freeze-dried) powder.
The protein was lyophilized from a concentrated (1mg/ml) solution with 0.0045mM NaHCO3.
It is recommended to reconstitute the lyophilized PRLR-ECD in sterile 18M-cm H2O not less than 100µg/ml and not more than 1 mg/ml, which can then be further diluted to other aqueous solutions.
Lyophilized PRL-R although stable at room temperature for 1-2 weeks, should be stored desiccated below -18°C or preferably even at -80°C to prevent dimer formation. Upon reconstitution PRL-R should be stored sterile at 4°C between 2-7 days and for future use below -18°C. For long term storage at 4°C it is recommended to add a carrier protein (0.1% HSA or BSA).
Please prevent freeze-thaw cycles as they cause oligomerization of the protein.
Greater than 97.0% as determined by:
(a) Analysis by RP-HPLC.
(b) Analysis by SDS-PAGE.
(c) Gel filtration at pH 8 under non denaturative conditions.
Amino Acid Sequence:
The sequence of the first five N-terminal amino acids was determined to be Gly-Lys-Pro-Phe-Ile.
Dimers and Aggregates:
Less than 3%.
Activity is determined by the dose-dependant inhibition of PRL-stimuled proliferation of Nb2 cells and by high affinity binding of oPLR and other lactogenic hormones.
Less than 0.1 ng/µg (IEU/µg) of rbPRLR-ECD (24 kDa).
Protein quantitation was carried out by two independent methods:
1. UV spectroscopy at 280 nm using the absorbency value of 2.79 as the extinction coefficient for a 0.1% (1mg/ml) solution. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).
2. Analysis by RP-HPLC, using a standard solution of PRL-R as a Reference Standard.
PLR's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals.