Catherine Fenselau, professor of chemistry and biochemistry, University of Maryland, College Park
Identifying molecular mechanisms of drug resistance in breast cancer
Fenselau works with several drug-resistant and drug-sensitive cell lines, and she wanted a cheap and simple way to compare protein abundance among them.
Fenselau's approach, proteolytic 18O labeling, is simplicity itself. "It works, we know how to do it, and it's less expensive than other methods, especially metabolic labeling," she says. Two protein extracts are digested to peptides, one in normal 16O water, and the other in labeled 18O water. Each peptide produces two peaks differing in mass by 4 Daltons (because two water molecules are used in the cleavage reaction); the ratio of peaks reveals how the peptide's abundance in one sample compares with the...