Jeremy Gunawardena recently wrote a very nice minireview about the lessons of the Michaelis-Menten equation for model-building (also available here). Michaelis-Menten is an equation with many lessons for modern systems biologists (as I’ve discussed before) and is so deeply ingrained in biochemistry that I am sure that most people who learn about it regard it as simply a fact of life; but instead, it is a simplified way of expressing certain facts about life, i.e. a model. When Michaelis and Menten developed it, it was a highly theoretical construct that assumed the existence of a chimeric creature called the enzyme-substrate complex, which would not be observed until 30 years later. Jeremy calls the enzyme-substrate complex the “elephant in the room”, and argues that what was remarkable about Michaelis and Menten’s accomplishment was not the fact that it fitted the experimental data, but that by doing so it provided evidence for something unseen. Provocatively, he argues that the fact that MM was adopted so quickly by biologists, despite this great hole in the evidence, indicates that biology is more theoretical than physics; and that this, in turn, is because biology is more complicated than physics and needs all the help it can get. Go and read it, and discuss.
Gunawardena J (2012). Some lessons about models from Michaelis and Menten. Molecular biology of the cell, 23 (4), 517-9 PMID: 22337858