A major portion of most biochemical investigations involves the purification of the materials under consideration because these substances must be relatively free of contaminants if they are to be properly characterized. This is often a formidable task because a typical cell contains thousands of different substances, many of which closely resemble other cellular constituents in their physical and chemical properties. Furthermore, the material of interest may be unstable and exits in vanishingly small amounts. Typically, a substance that comprises less than 0.1% of a tissue’s dry weight must be brought to approximately 98% purity. Purification problems of this magnitude would be considered unreasonably difficult by most synthetic chemists. It is therefore hardly surprising that our understanding of biochemical processes has by and large paralleled our ability to purify biological materials. Read the rest of this entry »