The body from gene to protein

Biochemistry is a rapidly expanding subject taught to biological science students but also to students of medicine, pharmacy, nursing, dentistry and nutrition. The question is whether any textbook is sufficiently authoritative and inclusive to cover the needs of all these students while not requiring wheels to carry it around.

The three texts under review have served students for many years and are now available in new, expanded editions. They are by American authors, and designed for US higher education, so one might ask how well they will support biochemistry classes in the UK.

My own experience is in teaching biochemistry to pharmacy students, as part of four different classes ("courses" in American parlance) in an MPharm course. To find out about other courses, I surveyed UK reading lists for subjects ranging from chemistry to dentistry. It seems that texts such as these are regarded as useful background reading for biochemistry lectures.

However, no one, even in "straight" biochemistry, seems to base a lecture class entirely on one textbook.

Among the recommended textbooks in the 13 reading lists surveyed, there were six top authorial teams, which included those for Biochemistry by Donald Voet and Judith Voet and Lehninger Principles of Biochemistry by David Nelson and Michael Cox. However, the most popular biochemistry textbook was neither of these, but a book now in its fifth edition, Biochemistry by Jeremy Berg, John Tymoczko and Lubert Stryer.

Popularity does not necessarily imply quality, however, and many of us are creatures of habit or old lecture notes, sticking to one textbook, edition after edition. The problem is how to distinguish between these three textbooks and decide which might be best for a particular class.

Each has two authors, and also has large editorial teams and the advice of outside experts, and therefore all three should be accurate and complete.

To confirm this, I chose some of my favourite topics, either from lectures or my research interests - admittedly a biased selection, but one in which errors or omissions would be easy to pick out - and checked to see if they were mentioned in each text, and how accurately.

Drug design is particularly important to pharmacists, and the development of ACE (angiotensin-converting enzyme) inhibitors is a success story of modern drug design. Only Voet and Voet cover this topic, in an excellent new section. Drugs usually enter cells by passive diffusion, which is discussed in detail only by Voet and Voet. They are often metabolised in the liver by a pathway involving cytochrome P450, mentioned briefly by Nelson and Cox, and at length by Voet and Voet. Only Nelson and Cox discuss the interesting family of ABC transporters.

Regarding research in lipids and the retina, I looked for rhodopsin and related G-linked receptors. The fascinating story of rhodopsin and its function in the visual cycle is missing from Biochemistry by Reginald Garrett and Charles Grisham, who mention it only in the context of vitamin A-binding and the total synthesis of rhodopsin's gene. Nelson and Cox are particularly good at describing the visual system.

Fatty acids are an ignored field, though they have an important role in nutrition. All three books mention the omega-3 and omega-6 essential fatty acids, but do not always explain why they are required. Phytanic acid, produced in ruminant animals from phytol derived from chlorophyll, has an interesting story because it has its own metabolic pathway, and defects can lead to a severe condition, Refsum's disease. All three books mention this condition, but only Voet and Voet give a good account. Garrett and Grisham are wrong concerning therapy, recommending a diet lacking all green vegetables and meat from vegetable-eating animals. (Fish and ruminant animals are the problem: only dairy products, beef, lamb and fish should be avoided.) Finally, I looked for the apolipoproteins, particularly "apo E", since the E4 isoform is linked to Alzheimer's disease. Voet and Voet have the best discussion of these proteins, whereas Garrett and Grisham mention them only in a table, with the wrong name.

All three textbooks are well organised and include summaries and questions at the end of each chapter, with answers in a separate book for Voet and Voet (an extra expense for students). There are also course guides for lecturers, PowerPoint presentations, CD-Roms, helpful websites and other paraphernalia to accompany the book, which I have not evaluated.

The books vary in the space they devote to the three main categories of structure, metabolism and genetic information. Voet and Voet, which is the biggest of the three books (twice the size of my undergraduate biochemistry text), devotes the most space, proportionately, to genetic information.

Nelson and Cox are a bit stronger on metabolism, and Garrett and Grisham have a large structural section. The style of Voet and Voet is the simplest, whereas Garrett and Grisham's book is overembellished with pictures of the authors' children, pets and other animals, quotations, essays by "outstanding biochemists", boxes titled "A deeper look", "The essential question", "Key questions" and so forth. As a result, some of the diagrams and captions are so small that a magnifying glass is required.

I would recommend Voet and Voet for background reading on just about any biochemical subject, as long as you do not have to carry it to class every day (it weighs 3.4kg in paperback). Nelson and Cox, too, have produced a very reliable text.

Carolyn Converse is senior lecturer in pharmaceutical sciences, Strathclyde University.