Http://www.lifetechnologies.com/mx/es/home/references/molecular-probes-the-handbook/reagents-for-modifying-groups-other-than-thiols-or-amines/reagents-for-modifying-alcohols.html

Tyrosine is relatively easy

http://www.sciencedirect.com/science/article/pii/S1074552110000773

Iodination with I125 is a common application

A larger list can be found here

http://www.amazon.com/Chemical-Reagents-Protein-Modification-Third/dp/0849319838/ref=sr_1_1?s=books&ie=UTF8&qid=1380838991&sr=1-1&keywords=Chemical+Reagents+for+Protein+Modification

Serine and threonine are considerably less reactive

Difficult, best to incorporate modified amino acids during synthesis, or leave one unprotected during synthesis, and modify before total deprotection

It is possible, the weak base is added to dilute NaOH or Na2CO3

If you ar using Solid-Phase Peptide Synthesis, it's easy and very common work. Choose the right protecing group to remove them one by one or grouped, based on your planned final structure.

If you are working on proteins or free peptide, see previous answers, they give good products.

Please find the details of one of my articles from which you would get some information.

N. Mallesha, S. Prahalad Rao, R. Suhas and D. Channe Gowda, “An Efficient

Synthesis of tert-Butyl Ethers/ Esters of Alcohols/ Amino Acids using Methyl

tert-Butyl Ether”, Tetrahedron Letters, 2012, 53, 641-645.

Depends on what you want to modify. In our works we modify hydroxyl group with iodine, tosyl ester or N-hydroxyphthalimide, and after that it is easy to replace it how do you want. You can see this in some of our publications. If you are interested in this contact me, and I can give you some working protocols.

@tatanya... Willll your protocols also affect hydroxyl in sugar chains attached to proteins or only amino acids..? If onlly maino acids, then please provide protocols...

Saraswat, Its trivial to modify Tyr, Ser or The hydroxyls selectively, all you need to do is to introduce trityl protected Ser, Thr or Tyr. Then after peptide synthesis is completed selectively remove Trityl under mild acidic conditions (2% TFA, 2% TES, CH2Cl2). Only O-Trt gets deprotected (rapid, < 2min). You can modify residues accordingly then.

Are you talking about protein or synthetic peptide modification?

I am talking about proteins...

The 'million dollar question', how to selectively target amino acids for modification. Not sure if you want to modify all serines, threonines and tyrosines simultaneously, or just want to target only one of these amino acids (site-specifically) but for what it is worth:

Tyrosine can be modified by A: a tyrosine-click reaction between diazodicarboxylate molecules and tyrosine (1), B: by palladium-catalyzed π-allylation (2), C: a three-component Mannich-type coupling reaction with aldehyde and aniline reagents (3), D: reaction by a nickel(II)-mediated radical coupling with magnesium monoperoxyphthalate as an oxidant (4).

(1):

Ban, H.; Gavrilyuk, J.; Barbas, C. F. (2010) Tyrosine bioconjugation through aqueous ene-type reactions: a click-like reaction for tyrosine. J. Am. Chem. Soc. 132, 1523–1525.

Ban, H.; Nagano, M.; Gavrilyuk, J.; Hakamata, W.; Inokuma, T.; Barbas, C. F. (2013) Facile and stabile linkages through tyrosine: bioconjugation strategies with the tyrosine-click reaction. Bioconjugate Chem. 24, 520–532.

(2):

Tilley, S. D.; Francis, M. B. (2006) Tyrosine-selective protein alkylation using pi-allylpalladium complexes. J. Am. Chem. Soc. 128, 1080–1081.

Antos, J. M.; Francis, M. B. (2006) Transition metal catalyzed methods for site-selective protein modification. Curr. Opin. Chem. Biol. 10, 253–262.

(3):

McFarland, J. M.; Joshi, N. S.; Francis, M. B. (2008) Characterization of a three-component coupling reaction on proteins by isotopic labeling and nuclear magnetic resonance spectroscopy. J. Am. Chem. Soc. 130, 7639–7644.

(4):

Kodadek, T.; Duroux-Richard, I.; Bonnafous, J.-C. (2005) Techniques: Oxidative cross-linking as an emergent tool for the analysis of receptor-mediated signalling events. Trends Pharmacol. Sci. 26, 210–217.

Meunier, S.; Strable, E.; Finn, M. G. (2004) Crosslinking of and coupling to viral capsid proteins by tyrosine oxidation. Chem. Biol. 11, 319–326.

You can find partial answer in this review:

Natural covalent complexes of nucleic acids and proteins: some comments on practice and theory on the path from well-known complexes to new ones.

Y F Drygin

Nucleic Acids Research 12/1998; 26(21):4791-6. ·

Please pay attention to discussion on modified Ser and Thr residues.