Chemical Biology vs. Biological Chemistry

"What is chemical biology and how is that different from biochemistry?"

This is the one question I am often asked at family functions, by other students, and sometimes even by other chemists who are not familiar with the discipline. The answer: it’s complicated!

If you search for "chemical biology" on the internet, the results would include hundreds of websites, college syllabi, and opinion pieces, each attempting to describe the field or explain the methodology used by researchers. And while there are some excellent resources about this field, many more results simply describe the idea that chemical biology is “something chemical” associated with “something biological” (1).

Even the experts, those researchers pushing the frontiers of the field, have difficulty nailing down a unified description of what constitutes chemical biology--some arguing that is is the techniques being utilized while others arguing that it is the type of questions being asked. Personally, I like Christopher Walsh's definition: "The goal [of chemical biology] is a seamless application of chemical principles to decipher complexities in biology and bring scientists trained in chemistry to full engagement on biological projects," (2).


This is how I like to simplify the difference:

Adapted from (3). 

Biological Chemistry (aka Biochemistry): The study of the chemical properties of biological systems.
Traditionally, biochemists study biological systems in living organisms. They are interested in the role and function of biological molecules. Common techniques may include enzyme kinetics, mutagenesis, or pharmacology.

Chemical Biology: Manipulating biological systems using the tools/techniques of chemistry.
Conversely, chemical biologists might better be described as engineers. They want to use the tools of chemistry to study or "tweak" biological systems. Common techniques include directed evolution, metabolic engineering, or rational drug design.


Although I've just spent time developing a distinction between the two fields, many labs and many scientists frequently employ techniques of both in their research. For example, labs that are very skilled at synthesizing organic small molecules might also employ mutagenesis to tweak their enzyme target of interest (4). Or, a graduate student trained in biophysical methodology might elect to do a more chemically-oriented post-doc, applying fresh perspective to new problems.

Working at the intersection of biology and chemistry sometimes has interesting consequences, but I feel that one of the main barriers between these fields is the lack of cross-talk. Advances in one field may be overlooked, simply because the results are presented in an unfamiliar language. In my opinion, this is why interdisciplinary training is so valuable. Training in biochemistry or chemical biology allows scientists not only to "speak the language" of each field, but to apply the best techniques to the most interesting biological questions.




Additional Reading:
1. Thomas, P. "The Chemical Biologists," Harvard Magazine, 2005, 38-47.

References:
1. Mahapatra, A. "Chemistry or Biology? The debate continues..." ACS Chem. Biol. 2009, 4, 969-970.
2. Walsh, CT. "Natural Insights for Chemical Biologists,"Nat. Chem. Biol. 2005, 1, 122-144.
3. Calderone, CT. BIOL/CHEM 359. Lecture on Chemical Biology. Presented at Macalester College, St. Paul, MN, Sept. 8, 2010.
4. Shah, K. et al. "Engineering unnatural nucleotide specificity for Rous sarcoma virus tyrosine kinase to uniquely label its direct substrates," Proc. Natl. Acad. Sci. USA, 1997,  94, 3565-3570.