Stable Isotope Assays for Targeted Protein Half-Life

Understanding Targeted Protein Half-Life

Protein turnover reflects the balance between synthesis and degradation, and directly influences protein stability in vivo. Using D₂O as a tracer, deuterium becomes incorporated into amino acids during de novo synthesis and ultimately into newly formed proteins. As these proteins accumulate label over time, predictable isotopic patterns emerge that can be quantified by mass spectrometry.

By analyzing how mass isotopomer distributions evolve—such as M0 depletion or enrichment plateaus—researchers can derive fractional synthesis rates, turnover rate constants, and half-lives for proteins across tissues or targeted protein classes.