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Unformatted text preview: Asn and Gln – both polar, hydrogen-bond donors and acceptors Extreme pHs and high temperature Asp and Glu Asn more likely than Gln Amino groups (such as that of Lysine) can be detected by 2-4-6-trinitrobenzene sulfonate (TNBS) which absorbs at 367 nm Histidine – imadazole ring In the non ionized form, nitrogen with hydrogen atom is an electrophile and donor for hydrogen bonding, and the other hydrogen atom is a nucleophile and acceptor for hydrogen bonding Aromatic side chains – Phe, Tyr Trp Responsible for most of the UV absorbance and fluorescence properties of proteins Phe – non polar, chemically unreactive Tyr – because of OH group, electrophilic substitutions -hydroxyl group can participate in OH bonding-electrophilic attack occurs at ortho position BULKINESS increases hydrophobicity 4.1.1 – impenetrable volume of atoms are defined by van der Waals radius...
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- Fall '08
- Amino Acids, peptide bond