CC1 LEC Protein - Liver Fx

• consists of carbon, hydrogen, oxygen, nitrogen, and sulfur


  Proteins
• % nitrogen makes them different from carbohydrates and lipids


  16%
• composed of polymers of covalently linked amino acids

  Macromolecules
• ranges from ~6000 insulin to several millions


  Molecular weight
• most are synthesized by and secreted by

  ribosomes; Hepatocytes - liver
• building blocks of proteins

  Amino Acids
• sequential number, order, and chemical identity of AA determine the structure of protein and functions

  Proteins
• 1. Carbohydrates
  2. Lipids
  3. Proteins
  4. Nucleic Acids


  Biological Macromolecules
• CHO

  1:2:1


  Carbohydrates
• CHO

  1:2:<1


  Lipids
• react both as acid and base and are amphipathic which means it is both polar (hydrophilic) and non polar (hydrophobic)


  Amphoteric
• H+ acceptor

  Amino group
• H+ donor

  Carboxyl group
• 1. Amino group
  2. Carboxyl group
  3. Alpha carbon
  4. Side chain


  Composition of Amino acids
• gives each amino acid its particular unique characteristics

  Side chain - R group
• D (carbohydrates) and L (proteins) form


  Chiral nature
• all are L forms except:

  GLYCINE
• 1. Non polar - hydrophobic and uncharged
  2. Polar - hydrophilic and uncharged
  3. Acidic - polar and charged
  4. Basic - polar and charged


  4 subgroups of Amino Acids
• 135 kDA


  Average Molecular Weight
• linked together by peptides (amide) bonds, formed when the carboxyl group of one AA attaches to the amino group of another AA, forming one molecule of water as a by-product


  Amino Acids
• 9 out of 20 key amino acids that cannot be synthesized by the human body, thus be obtained from diet

  Essential Amino Acids
• • Histidine
  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan
  • Valine


  Essential Amino Acids

  *Mnemonic - I Like Light That Tries Making Home Very Pretty
• • Arginine
  • Cystine
  • Glutamine
  • Glycine
  • Proline
  • Tyrosine


  Conditionally Non-Essential
• • Alanine
  • Asparagine
  • Aspartate
  • Glutamate
  • Serine


  Non-Essential
• can be produced by the bodies at a certain times only such as pregnancy

  Conditionally Non-Essential
• can be produced by the body

  Non-Essential
• • type of R group present in the amino acid
  • pH of the solution 


  AA are amphoteric; the charge depends on the
• In a basic solution, a proton dissociates from the carboxyl group, forming -COO-(anion), causing a negative net charge
• In an acidic solution, there is excess proton which attaches to the amino group, forming -NH3+ (cation), causing a positive net charge
• They all have variations in what part of structure is protonated depending on the pH of the solution; pH is 7.35 to 7.45
• equal depends on R group and has a pH value in which an amino acid has no net charge


  Isoelectric Point (pI)
• 1. Primary
  2. Secondary
  3. Tertiary
  4. Quaternary 


  4 levels of structures
• All proteins have this structure and it is the most fundamental level


  Primary Structure
• • the number, kinds and sequence of AA in polypeptide chain
  • it determines the identity of the protein, molecular structure, function and binding capacity, and recognition ability
  • any change can significantly alter the protein

  Primary Structure
• • Amino Acids - building blocks of proteins;
  • amino acids + carboxylic acids are linked by peptide bonds
  • chain of AA - polypeptide
  • large polypeptide - Proteins
• it is the result of many hydrogen bond; peptide bond

  Secondary Structure
• • it involves the winding of the polypeptide chains maintained by hydrogen bonds between amino and carboxyl groups
  • gives stability to the protein molecule


  Secondary Structure
• • Alpha helix (Coil, spring-like)
  • Beta pleated sheet (flat, corrugated)
  • Bend
  • Random (no apparent pattern)


  Specific 3D conformations of secondary structures
• Overall shape are determined by primary and secondary along with side chains
• • actual or overall 3D configuration or shape of the polypeptide chain
  • involves the folding pattern of the protein maintained by electrostatic, disulfide and hydrogen bonds
  • may be globular or fibrous
  • destroyed by denaturation

  Tertiary Structure