Table 1. PKM2 is modified at multiple sites by HNE and ONE.

Recombinant PKM2 was modified in vitro with increasing concentrations of HNE or ONE, adducts were reduced, and proteins resolved by SDS-PAGE prior to in-gel digestion and analysis by LC-MS/MS.

Peptide	Observed m/z	Theoretical m/z	Charge	Mass Error (ppm)	Residue	Modification	Electrophile
NTGIIC*TIGPASR	730.9112	730.9107	2	0.68	Cys49	Michael Adduct	HNE and ONE
IENH*EGVR	556.3110	556.3089	2	3.77	His274	Michael Adduct	HNE and ONE
CC*SGAIIVLTK	661.8759	661.8747	2	1.81	Cys424	Michael Adduct	HNE and ONE
SAH*QVAR	463.7764	463.7745	2	4.10	His439	Michael Adduct	HNE and ONE
NIK*IISK	486.3305	486.3286	2	3.91	Lys256	Michael Adduct	HNE
VLGEK*GK	443.7864	443.7840	2	5.41	Lys261	Ketoamide	ONE