Heavy hitting: Using water to label humans

Monitoring protein dynamics, compared to measuring static protein expression profiles taken with snapshot evaluations, have recently been the focus of proteomics studies examining tissue or blood samples where time course changes occur. Using deuterium oxide (²H₂O) to label amino acids is a useful method to monitor protein turnover rates. The synthesis rate for individual proteins is calculated from the rate of ²H incorporation into specific proteins analyzed by high resolution MS. In this issue, Wang and colleagues measured the plasma protein turnover dynamics in healthy humans by in vivo ²H₂O labeling [Wang, D. et al., Proteomics Clin. Appl. 2014, 8, 610-619]. The authors developed and validated a safe and accessible ²H₂O administration protocol to record the turnover dynamics of 542 plasma proteins using MS. Their study demonstrates a promising new way to evaluate plasma protein dynamics in clinical trials where such knowledge could help for prognosis and evaluating treatment efficacy.