2011-2012 Catalogue - PeproTech, Inc.

www.peprotech.com2011-2012 CatalogueCytokines - Technical FAQINFORMATION & TECHNICAL SUPPORTBefore releasing our cytokines and cytokine productsfor sale they are thoroughly analyzed to ensurethe following qualities:1. Authenticity: by N-terminal sequence analysisand, when possible, by SDS-PAGE, RP-HPLC, and Mass Spectrometry analyses versusstandards.2. Purity: by SDS-PAGE and RP-HPLC analysis3. Biological Activity: by the relevant in vitro or in vivobioassay.4. Protein content: by UV spectroscopy, SDS-PAGEanalysis and, when possible, by HPLC analysis versusthe calibrated standard solution.5. Endotoxin contamination: by kinetic LAL method.6. Microbiological contamination: by membrane filtrationmethod; protein solutions are sterile-filtered priorto vialing.The relevant information relating to each productappears on the Certificate of Analysis that is shippedwith the product. Please read this information carefullyto obtain useful instructions for reconstitutionand storage. If, after reading the data sheet, you needadditional information, please review the followingset of questions and answers, or call our technicalservice department at 800-436-9910.1. What should I know about the stability of your proteinproducts?Unless otherwise mentioned on the product informationsheet, all of our products are formulated insuch a manner that the lyophilized proteins are verystable at room temperature. However, we recommendstoring lyophilized products at -20 o C.For reconstituted solutions of most products, werecommend short-term storage at 4 o C. For longerterm storage the protein solution should be storedwith a carrier protein (eg. 0.1%BSA) in workingaliquots and stored frozen at -20 o C. Please keep inmind that every freeze/thaw cycle may cause somedenaturation of the protein.2. Why can't I see the protein pellet in the vial?Unlike many protein products available on themarket, PeproTech products are not formulatedwith carrier protein or other additives (e.g., BSA,HSA, sucrose, etc.) and are often lyophilized witha minimum amount of salt. As a result, the smallamounts of protein can be deposited on the vial duringlyophilization as a thin and sometimes invisiblefilm. Before opening, we recommend centrifugingeach vial in a microcentrifuge for 20-30 seconds todrive any protein that may be lodged in the cap or onthe side to the bottom of the vial. Our quality controlprocedures assure that each vial contains the correctamount of product.3. What is the relationship between the specific activityexpressed as an ED 50and as units/mg?The ED 50is defined as the cytokine concentrationat which the activity is 50% of the maximumresponse. This method of expressing potency shouldonly be used for cytokines whose dose-responsecurves are sigmoidal in shape. The formula forconverting the activity as an ED 50in ng/ml to specificactivity in units/mg is:1 x 10 6 specific activity (units/mg)ED 50(ng/ml)=4. Which cytokines show cross-species activity?With a few exceptions, most human cytokines areactive on mouse cells. Many mouse cytokines areactive on human cells, but may show lower specificactivity than the corresponding human cytokine.A few human cytokines, such as IL-7, even exhibithigher specific activities on mouse cells than do thecorresponding mouse cytokines. The interferons, GM-CSF, IL-3, and IL-4 are known to be species-specificwith very little, if any, activity on non-homologouscells. In contrast, the FGF's and neurotrophins arevery highly conserved and show excellent activity oncells of other animal species.152To Order: EC: Tel: +44 (0)20 7610 3062 • email: info@peprotech.co.ukBestellungen: AUSTRIA: Tel: +43 (0)1 405 9696 • email: info@peprotech.atObjednávky: Česká Rep.: Tel: +420 225 992 284 • email: info@peprotech.cz