Enzymes Quotes

“As we have seen, enzymes are minute but powerful molecular machines, machines that carry out various sorts of chemistry at phenomenal speed and with extraordinary accuracy. Chapter 1 closed with a quotation from Frederick Gowland Hopkins, who suggested almost ninety years ago that it was ‘difficult to exaggerate the importance to biology, and to chemistry no less, of extended studies of enzymes and their action’. A prophetic statement indeed, but even Hopkins could not have dreamt of the sweeping impact of these amazing molecules on science, technology, medicine, and our understanding of life itself.”
― Paul Engel, Enzymes: A Very Short Introduction

“Protein engineering has moved from a wary adventure on the part of a few pioneering groups in the 1980s to a routine tool used around the world today on a vast range of targets, and with immense power for fine-tuning the properties of enzymes and other proteins for practical applications. In particular, enzyme catalysis has at last gained widespread acceptance as a tool for chemistry, and, because enzyme catalysis avoids the need for high temperatures and pressures and toxic waste streams, it has become the basis of what is now generally known as ‘green chemistry’. One recent indicator of this remarkable shift in the relationship between enzymology and mainstream chemistry was the share in the 2018 Nobel Prize for Chemistry for Professor Frances Arnold at Caltech who has in recent years pioneered major advances in the methodology for efficient development of novel biocatalysts.”
― Paul Engel, Enzymes: A Very Short Introduction

“In the management of cancer, a big problem with traditional methods has been that the patient can perceive the treatment as almost worse than the disease, since the chemicals given to attack the cancer cells also attack many other types of cell. In the frontline of cancer drug development today is a sophisticated range of drugs with names ending in ‘mab’, standing for monoclonal antibody. One half of the therapeutic molecule is an antibody against specific proteins on the surface of the target cancer cells and the other half is an enzyme. (This strategy relies on the surprising fact that, often, if the genes for two proteins are joined end to end, they successfully encode an enlarged protein combining both functions—i.e. both halves still fold successfully.) When this delivery vehicle reaches its destination, the whole molecule is taken up into the cells. The other half, chemically attached to the antibody, is the enzyme ‘warhead’ that inflicts the damage. The enzyme itself could be one that, for example, attacks the cells’ nucleic acids.”
― Paul Engel, Enzymes: A Very Short Introduction

“The darker side of this story is that parents in such (cot death) cases have often had their tragedy compounded by suspicion that they have killed their child. In one particularly sad case a few years ago an ‘expert’ witness informed a UK court that the chances of a couple’s first cot death through natural causes were 1 in 8,000, and, that, following the second cot death in the same family, the chances of that were 1 in 8,000 x 8,000 (i.e. 1 in 64 million). The mother went to prison because the ‘expert’ failed to understand that, if the first death, however unlikely, had a genetic cause, then the chances of the same defect affecting the next child were 1 in 4. For a recessive condition (see above), the assumption is that the two parents are carriers, each carrying one ‘bad’ copy and one ‘good’ copy of the gene. They are therefore unaffected themselves but both have a 50:50 chance of passing on the bad copy to their offspring. Hence a 25 per cent chance that the child will be affected and a 50 per cent chance that the child will be unaffected but also be a carrier like the parents.”
― Paul Engel, Enzymes: A Very Short Introduction

“Although a few enzymes (e.g. carbonic anhydrase) catalyse a single isolated reaction, most are part of a team that catalyses a series of reactions in which each enzyme picks up its predecessor’s product, taking it a step further to create a metabolic pathway. This pathway may be to build up, say, an amino acid from simpler starting molecules, or conversely to break down food molecules to yield new chemical building blocks and sometimes also to trap useable energy. Life is the combined outcome of this seemingly logical enzyme teamwork. Like most things in the living world, this gives the appearance of purposeful planning down to the last detail. Such meticulous perfection would in past eras have been confidently attributed to the attentive skill of an all-powerful Creator. Since Charles Darwin, however, we have an alternative way of explaining how things in the living world come to be the way they are. Darwin led us to understand that natural selection could bring about stepwise beneficial adaptation over thousands or even millions of years, and, in the 150 years since the Origin of Species, we have learnt far more about the genetic mechanisms that can bring about such change. Does this kind of thinking work at the molecular level when we come to look at metabolic pathways and individual enzymes?

In fact the study of enzymes and other proteins allows us to be a great deal more certain than Victorian biologists could be. Many of the distinctive biological characteristics studied in comparing animals and plants, like eye colour or wing shape, have turned out to be controlled by multiple genes, whereas, in looking at individual proteins, we are looking at the products of individual genes, and latterly we can even examine those genes directly. The possibility of determining protein amino acid sequences, and, more recently, the corresponding DNA sequences, allows comparison of the same enzyme from many species and also of enzymes catalysing different but similar reactions from a single species.”
― Paul Engel, Enzymes: A Very Short Introduction

“Most people have probably met enzymes in school biology as the agents responsible for digesting our food, breaking down the starch of pasta, rice, potatoes into sugar and so on. Many meet them again as they face their washing machine, stained sports clothes in hand, and wonder whether or not to use a ‘biological’ detergent, containing added but unspecified ‘enzymes’ to do mysterious things to the clothes. As it happens, in both contexts the enzymes’ function is very similar, breaking down large chemical molecules into smaller bits that will wash away. People do not generally realize, however, that enzymes have much wider and more diverse roles and that, in effect, they orchestrate the whole of life.”
― Paul Engel, Enzymes: A Very Short Introduction