From C&EN:

Peptide coupling agents can cause severe allergic reactions

Researchers can develop sensitivities to the compounds, to the point of anaphylaxis

by Leigh Krietsch Boerner

JANUARY 2, 2020

If you're a chemist working with peptide coupling agents, you can literally become allergic to the lab, according to a new report. Over the course of three years, graduate student Kate McKnelly of the University of California, Irvine, developed an allergy to the coupling agents HATU, HBTU, and HCTU so severe that she can no longer be in the building where they're used. She and her research adviser James Nowick found that her allergy to the uronium coupling agents is not an isolated incident, and that many peptide coupling reagents are sensitizers and should be handled with extreme care (J. Org. Chem. 2019, DOI: 10.1021/acs.joc.9b03280).

Peptide coupling agents help form amide bonds between a carboxylic acid and an amine, so the compounds have the potential to modify human proteins. This property makes the agents potential sensitizers, chemicals that can cause people who are regularly exposed to them to develop an allergy. "This is something that has been passed around anecdotally and in the toxicological literature, but has not been published in places that organic chemists would see," Nowick says. The authors found about 10 other examples of the allergy in the toxicology literature, but don't have exact numbers on how common the allergy is.

After years of repeated exposure to the agents, McKnelly has to carry an epipen, can no longer work in the lab, and has to ask labmates to change their clothes before coming into contact with her. At first, McKnelly didn't know where her symptoms were coming from, but she began to suspect it was lab-based after she=E2=80™d notice her reactions while weighing out the coupling reagents in the lab. "Sometimes I would sneeze or my nose would get runny," she says, but she was trying not to jump to conclusions. "I didn=E2=80™t really know for sure until I had my anaphylactic reaction."

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