Acetylated lysine visualized using SMC-153, tested on Bouin's fixed paraffin-embedded  backskin sections of transgenic mice. Courtesy of Dr. Turksen, Ottawa Health Research Institute, Canada.

Post-translational modifications of proteins play critical roles in the 
regulation and function of many known biological processes. Proteins can
 be post-translationally modified in many different ways, and a common 
post-transcriptional modification of Lysine involves acetylation (1). 
The conserved amino-terminal domains of the four core histones (H2A, 
H2B, H3 and H4) contain lysines that are acetylated by histone 
acetyltransferases (HATs) and deacetylated by histone deacetylases 
(HDACs) (2). Protein posttranslational reversible lysine Nε development 
(5).

1. Yang XJ. (2005). Oncogene. 24:1653-1662.
2. Hassig, C.A. and Schreiber, S.L. (1997). Curr. Opin. Chem. Biol. 1(3): 300-308.
3. Yang XJ. (2004). Bioessays 26:1076-1087.
4. Hughes, R.E. (2002). Curr. Biol. 12: R141-R143.
5. Vigushin, D.M. and Coombes, R.C. (2004). Curr. Cancer Drug Targets 4: 205-218.