Biochemistry C 785 Study Guide

WGU Biochemistry C 785 Study Guide Page 10 Video Notes for Units 2-7 Unit 2 – Amino Acids, Peptide Bonds, Protein Structure  Amino Acid: building blocks of proteins  Monomer: single amino acid  Polymer: amino aci ...

WGU Biochemistry C 785 Study Guide Page 10 Video Notes for Units 2-7 Unit 2 – Amino Acids, Peptide Bonds, Protein Structure  Amino Acid: building blocks of proteins  Monomer: single amino acid  Polymer: amino acid chain of linked monomers called polypeptides  Amino Group: N with at least 1 H, can be NH2 or NH3  Hydrogen Hat: between amino group and carboxyl group, attached to alpha carbon  Variable Group “side chain” “R”: unique portion of amino acid  Carboxyl Group: C with 2 attached O’s, can be COOH, or COO  Hydrophobic Amino Acid: consists only of carbons and hydrogens end in H, CH, CH2, CH3 – they are nonpolar –Hydrophobic interactions occurs between two nonpolar amino acids H, CH, CH2, CH4, are the weakest type of bond – but the most important type for protein structure – are broken with heat (increased temperature)  Polar Amino Acid: end in OH, NH, SH, create hydrogen bonds, can be broken by changes in pH or changes in salt concentration.  SH: Disulfide bond/bridge made by SH side chains, is strongest, fewest in number, and only broken with reducing agents  Peptide Bonds: form at amino group and carboxyl group, “loss of H2O”  Ionic Bonds: occurs between two amino acids with opposite charges (charged amino acids, -/+, negative is acidic positive is basic), are broken with pH changes or changes in salt concentration  Dehydration Synthesis: when two molecules are covalently bonded with loss of a water molecule (H20)  one provides hydroxyl group OH and the other provides hydrogen H.  Amino group and carboxyl group both give up something and then they bind and form a new bond  polymer chain  Hydrolysis: addition of a water molecule H2O to break a bond, breaks polymers  4 Levels of Protein Structure: Primary  linear chain of amino acids, Secondary  alpha helix and beta sheet shapes, create by Hydrogen bonds of polypeptide backbones Tertiary 3D, stabilized by side chains Quaternary  consists of two or more polypeptide chains, more than one subunit – tertiary and quaternary are mature structures that are properly folded.  Denaturation: high temperatures and various chemical treatments will denature a protein, causing it to lose its shape and ability to function “form=function”  it may renature when chemical and physical aspects of environment are restored to normal. Unit 3 – Enzymology and Catalytic Mechanism  Enzymes: are proteins, they catalyze reactions when properly folded, can be disrupted just like amino acids by heat, pH, etc., “enzymes are proteins that act as biological catalysts,  Lactose is a substrate that can be converted to glucose and galactose which are products by lactase which is an enzyme (enzymes usually end in “ase”). Enzymes lower the activation energy of a reaction “makes it easier and quicker”. People who are lactose intolerant do not have lactase that breaks it down into usable products. Excessive internal heat can denature hydrophobic interactions thus causing important enzymes to lose their function.  Enzymes bind a specific substrate and catalyze a specific reaction, speed up reactions, and decrease activation energy “faster and easier”  Substrates bind to an enzyme’s active site. When an enzyme is fully folded it creates an active site for the substrate to bind to. Tertiary/Quaternary enzymes have active sites only, fully mature enzymes, enzymes recognize specific substrates (lock and key) “enzyme specificity”  Enzyme 4-step Cycle: Step 1= substrate recognition, the substrate recognized a specific enzyme a