This article describes a sample preparation method based on heat-inactivation to preserve endogenous peptides avoiding degradation post-mortem, followed by relative quantitation using isotopic labeling plus LC-MS.
Correa, C. N., Fiametti, L. O., Mazzi Esquinca, M. E., Castro, L. M. d. Sample Preparation and Relative Quantitation using Reductive Methylation of Amines for Peptidomics Studies. J. Vis. Exp. (177), e62971, doi:10.3791/62971 (2021).