Review Question - QID 214604

A 71-year-old woman presents to the emergency department with a 2-hour history of severe abdominal pain associated with nausea and vomiting. She says that over the past day she has been experiencing more abdominal discomfort but that she did not start vomiting until the pain became extremely severe over the last few hours. Her past medical history is significant for hypertension for which she is taking lisinopril, and her past surgical history is notable for 2 low transverse cesarean sections. Physical exam reveals ecchymosis over her right groin as well as a tender irreducible mass in the femoral canal. Laboratory studies are obtained as follows:

Serum:
Na+: 141 mEq/L
Cl-: 91 mEq/L
K+: 3.9 mEq/L
HCO3-: 12 mEq/L
BUN: 24 mg/dL
Glucose: 138 mg/dL
Creatinine: 1.2 mg/dL
Lactate: 30.2 mg/dL

Which of the following enzymes likely has increased activity in this patient?