生物化学（英文版）Biochemistry-chapter 3 AA and primary structure of proteinpart 1.pptVIP

Chapter 3 Amino Acids and the Primary Structures of Proteins 3.1 Outline of Proteins 3.2 Structures of Amino Acids 3.3 Other Amino Acids and Amino Acid Derivatives 3.4 Ionization of Amino Acids 3.5 Chemical reactions of AAs: 3.6 Peptide Bonds Link Amino Acids in Proteins 3.7 Protein Purification Techniques 3.8 Amino Acid Composition of Proteins 3.9 Determining the Sequence of Amino Acid residues 3.10 Comparisons of the Primary Structures of Proteins Reveal Evolutionary Relationships 1. Proteins is most important biological functional molecules: (1) Enzymes, the biochemical catalysts (photosynthesis,thermophilic bacteria,HIV-1 revers transcriptase) (2) Storage and transport of biochemical molecules (Hb, Mb) (3) Physical cell support and shape (tubulin, actin, collagen) 3.1 Outline of Proteins (4) Mechanical movement (flagella, mitosis, muscles) (5) Decoding information in the cell (translation, regulation of gene expression) (6) Hormones or hormone receptors (growth hormone, insulin receptor) (7) Other specialized functions (antibodies, toxins etc) 2. Classification of proteins: (1) According to shape of protein molecules; Globular proteins Usually water soluble, compact, roughly spherical Hydrophobic interior, hydrophilic surface globular proteins include enzymes, carrier and regulatory proteins Fibrous proteins Provide mechanical support – not water soluble Often assembled into large cables or threads α-Keratins: major components of hair and nails Collagen: major component of tendons, skin, bones and teeth (2) According to polymerization of protein molecules; Monomeric proteins Oligomeric proteins (multimeric proteins) (3) According to conjugation of protein molecules; Simple proteins Conjugated proteins 3. Molecular size and Mr of proteins Proteins are homogeneous. Mr of proteins vary from about 6000 Da to 1 × 106 Da or more。 Usually insulin (5700 Da) or RNase (126000 Da