SRM/MRM ASSAY FOR THE INSULIN RECEPTOR PROTEIN

摘要

Provided are methods for quantifying the IR protein, IR-A isoform and/or IR-B isoform, directly in biological samples that have been fixed in formalin by the method of Selected Reaction Monitoring (SRM) mass spectrometry, or Multiple Reaction Monitoring (MRM) mass spectrometry. Biological samples are chemically preserved and fixed and are selected from tissues and cells treated with formaldehyde containing agents/fixatives. Protein samples are prepared using the Liquid Tissue reagents and protocol and the IR protein, and IR-A and/or IR-B isoforms, are quantitated in the Liquid Tissue sample by the method of SRM/MRM mass spectrometry by quantitating in the protein sample at least one or more of the peptides. These peptides can be quantitated if they reside in a modified or an unmodified form. An example of a modified form of an IR peptide is phosphorylation of a tyrosine, threonine, serine, and/or other amino acid residues within the peptide sequence.