L06_aminoacid_2013_462A

Amino acid residues dipepgde 2 tripepgdes 3

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 20 amino acids in proteins •  differ by nature of R group, side chain α ­amino group α ­carboxyl group Amino Acids form PepGde Bonds •  CondensaGon reacGon amide linkage (pep+de bond) polymer Amino Acids vs. Amino Acid Residues •  DipepGde (2), tripepGdes (3), oligopepGde (short), polypepGde (long) •  Amino acid residue – amino acid within pepGde N ­terminus C ­terminus Amino Acids: ClassificaGon •  Common amino acids can be placed in five basic groups depending on their R subsGtuents: –  other textbooks may categorize in different way •  •  •  •  •  Nonpolar, aliphaGc (7) AromaGc (3) Polar, uncharged (5) PosiGvely charged (3) NegaGvely charged (2) ring rigid more carbons, more hydrophobic Absorbance Spectra of AromaGc Amino Acids •  Tryptophan and tyrosine absorb ultraviolet light –  (also phenylalanine but weaker) •  Used to characterize proteins thiol disulfide bond not very polar Disulfide Bond FormaGon •  The oxidaGon of two cysteines Disulfide bond •  Stabilizes the structures of many proteins Both neutral and protonated forms present at physiological pH conjugate bases of Aspar+c Acid, Glutamic Acid What kinds of weak interacGons do...
View Full Document

Ask a homework question - tutors are online