Chapter 1 An overview of protein isolation (p. 1-2)
Isolating a protein may be compared to playing a game of golf. In golf, the player is faced with a series of problems, each unique and yet similar to problems previously encountered. In facing each problem the player must analyse the situation and decide, from experience, which club is likely to give the best result in the given circumstances. Similarly, in attempting to isolate proteins, researchers face a series of similar-yetunique problems. To solve these they must dip into their bags and select an appropriate technique. The purpose of this book is thus to fill the beginnerís "golf bag" with techniques relevant to protein isolation, hopefully to improve their game.
Developing a protein isolation is also somewhat like finding a route up a mountainside. Different routes have to be explored and base-camps established at each stage. Occasionally it will be necessary to return to the base of the mountain for further supplies, and haul these up to the established camps, before the next stage can be attacked. A successful climb is always rewarding and if an efficient route is established, it may become a pass, opening the way to further discoveries
1.1 Why do it?
This book is about the methods that biochemists use to isolate proteins, and so it may be asked, "why isolate proteins?" Looked at in one way, living organisms may be regarded as machines with features in common with the entities that we commonly think of as "machines". A typical machine is made of a number of parts which interact, transduce energy, and bring about some desired effect. Mechanical machines have moving parts, while electronic machines move electrons. "Engines" convert energy to mechanical motion. Internal combustion engines, for example, convert chemical energy to mechanical motion. Similarly, living organisms such as the human body are complex machines made up of many interacting systems. Proteins constitute the majority of the working parts of these systems and there are thus diverse reasons for isolating proteins, viz.;
• To gain insight. As with any mechanism, to study the way in which a living system works it is necessary to dismantle the machine and to isolate the component parts so that they may be studied, separately and in their interaction with other parts. The knowledge that is gained in this way may be put to practical use, for example, in the design of medicines, diagnostics, pesticides, or industrial processes. Many proteins may themselves be used as "medicines" to make up for losses or inadequate synthesis. Examples are hormones, such as insulin, which is used in the therapy of diabetes, and blood fractions, such as the so-called Factor VIII, which is used in the therapy of haemophilia. Other proteins may be used in medical diagnostics, an example being the enzymes glucose oxidase and peroxidase, which are used to measure glucose levels in biological fluids, such as blood and urine.
• For use in Industry. Many enzymes are used in industrial processes, especially where the materials being processed are of biological origin. In every case a pure protein is desirable as impurities may either be misleading, dangerous or unproductive, respectively. Protein isolation is, therefore, a very common, almost central, procedure in biochemistry.
• For use in Medicine. Many enzymes are used in industrial processes, especially where the materials being processed are of biological origin.
In every case a pure protein is desirable as impurities may either be misleading, dangerous or unproductive, respectively. Protein isolation is, therefore, a very common, almost central, procedure in biochemistry.
|
