what are proteins? amino acids
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What are Proteins? Amino Acids. Functions Enzymes Hormones Defense Structure Transport. Classification of Proteins (Chemical Composition) Simple Proteins – consist of ONLY Amino Acids Conjugated Proteins - have NON-Protein Portions as major component Glycoproteins Lipoproteins - PowerPoint PPT PresentationTRANSCRIPT
Proteins & Enzymes October 15 & 16, 2012
What are Proteins?Amino Acids
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Functions• Enzymes• Hormones• Defense• Structure• Transport
Proteins & Enzymes October 15 & 16, 2012
Classification of Proteins (Chemical Composition)Simple Proteins – consist of ONLY Amino Acids
Conjugated Proteins - have NON-Protein Portions as major component
• Glycoproteins• Lipoproteins• Phosphoproteins
Proteins & Enzymes October 15 & 16, 2012
Classification of Proteins (Shape)Globular Proteins – tightly folded, Water Soluble• Involved in: synthesizing, transporting, and
metabolizing• Such as: Hemoglobin, Hormones, Antibodies,
Enzymes
Fibrous Proteins – long, Water Insoluble• Involved in: Structural material of cells and tissues• Such as: Keratin, Elastin, Collagen
Proteins & Enzymes October 15 & 16, 2012
Globular Proteins
Fibrous Proteins
Proteins & Enzymes October 15 & 16, 2012
Protein StructurePrimary (1o) Structure• Peptide Sequence
• Amino Acids in Peptide Chain called, “Amino Acyl Residues”
• Peptide bonds form between Carbonyl Carbon & Amino Nitrogen, by removal of an O- from the Carbonyl and 2 H+ from the Nitrogen… Removal of H2O forms Peptide Bonds
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Secondary (2o) Structure• Folding of Peptide Sequence (1o
Structure)• Hydrogen Bonding utilizing Peptide-
Bonding Atoms• Intra-chain Hydrogen Bonding (α Helix)• Hair, Wool, Horns, and Feathers
• Inter-chain Hydrogen Bonding (β Pleated Sheets)• Silk
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Tertiary (3o) Structure• Folding and Twisting of 2o Structure
• Hydrophobic R groups cluster on inside of protein away from water
• Hydrophilic R groups cluster on outside of protein near water
• Hydrogen Bonding of non-peptide bonding atoms• Ionic Salt-bridges, COO-
● ● ● ● +NH3
• Disulfide Bonds (Disulfide Bridges) b/n SH-Groups• Cysteine not Methionine
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Quaternary (4o) Structure• Folding, Twisting, and Other Interactions b/n
different polypeptide strands in pre-existing 3o structure• Hydrophobic Bonding and Interactions• Hydrogen Bonding of Non-peptide Bonding Atoms• Ionic Salt-bridges, COO-
● ● ● ● +NH3
• Disulfide Bonds (Disulfide Bridges) b/n SH-Groups• Classifications: Dimers, Trimers, Tetramers, Pentamers,
Hexamers• EX: Hemoglobin – tetramer (2 α subunits & 2 β subunits)
• Each unit contains the Heme prosthetic group which contains Iron and is responsible for binding O2 in Blood.
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Enzymes
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012
Proteins & Enzymes October 15 & 16, 2012