|MadSci Network: Molecular Biology|
Hi Michael, This was a great question because it caused me to learn that there are chemical meat tenderizers (I thought everyone just pounded on their steaks like I do)! Chemical meat tenderizers are enzymes that cut proteins up into smaller pieces. Detergent has chemicals in it that cause proteins to stop binding to whatever it is they are usually binding to (generally your hands or clothes or dishes, but as you will see it can be other things). Normally DNA is wrapped around and packaged within clusters of proteins balls (picture a string wrapped around and around a series of baseballs in a row). The enzymes in the meat tenderizer essentially chop up the baseball-like proteins that the DNA is wrapped around, and then the chemicals in the detergent cause the DNA to stop sticking to the leftover pieces of the baseball/protein. That frees up the DNA/string to float around by itself in solution and bind to whatever dye it is that you are using to try to see it, and thus you do see it. If you didn't use the meat tenderizer, the baseball-like proteins would remain intact, and the detergent wouldn't be able to wash the DNA off. If you didn't use the detergent, the DNA would just stick to the pieces of the baseball-like proteins. But if you use both, the detergent is strong enough to wash the DNA off the pieces of the protein (just not the whole protein; if you want to know why you can write to me directly, but basically it has to do more complicated things like surface area and entropy). Good luck! Chris
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