PEP is an abbreviation for the three-carbon compound phosphoenolpyruvate.
In C4 plants, this compound is the primary CO2 acceptor.
It is an ester derived from enol of pyruvate and phosphate.
PEP also refers to the treatment of a health care worker who has been exposed to HIV by a needle stick which is an abbreviation for post-exposure prophylaxis.
PEP should only be used in an emergency and should be started within 72 hours of a recent probable HIV exposure.