PHARMA BIOCHEM

• Carbohydrates are the most abundant class of bioorganic molecules on planet Earth
• Carbohydrates constitute about 75% by mass of dry plant materials
• Photosynthesis


  1. Carbon dioxide from the air and water from the soil are the reactants

  2. Sunlight absorbed by chlorophyll is the energy source
• Functions of carbohydrates in humans

  • Structural elements
  • Energy reserves
• Carbohydrate


  A polyhydroxy aldehyde, a polyhydroxy ketone, or a compound that yields polyhydroxy aldehydes or polyhydroxy ketones upon hydrolysis
• Classification of carbohydrates by molecular size

  • Monosaccharides
  • Disaccharides
  • Oligosaccharides
  • Polysaccharides
• Chirality


  • Molecules that possess "handedness" exist in two forms: a "left-handed" form and a "right-handed" form
  • A chiral center is an atom in a molecule that has four different groups bonded to it in a tetrahedral orientation
  • A chiral molecule is a molecule whose mirror images are not superimposable
• Enantiomers


  Stereoisomers whose molecules are nonsuperimposable mirror images of each other
• Diastereomers


  Stereoisomers whose molecules are not mirror images of each other
• Right-handed and left-handed forms of a molecule often elicit different responses within the human body
• Dextrorotatory compound


  A chiral compound that rotates the plane of polarized light in a clockwise direction
• Levorotatory compound


  A chiral compound that rotates the plane of polarized light in a counterclockwise direction
• 1. isomer


  If the -OH group of the highest chiral carbon is in the right
• 1. isomer


  If the -OH group of the highest chiral carbon is in the left
• Optically active


  Compounds that interact with plane-polarized light and rotate the plane of polarized light
• Dextrorotatory compound


  Chiral compound that rotates the plane of polarized light in a clockwise direction
• Levorotatory compound


  Chiral compound that rotates the plane of polarized light in a counterclockwise direction
• D,L system


  System used to designate the handedness of enantiomers, extended to monosaccharides with more than one chiral center
• Determining D or L configuration of monosaccharides

  1. Number the carbon chain starting at the carbonyl group end

  2. Use the highest-numbered chiral center

  3. The -OH group of the highest chiral carbon determines the configuration

  4. If the -OH is on the right, it's a D-isomer

  5. If the -OH is on the left, it's an L-isomer
• Fischer projection formula is a two-dimensional structural notation for showing the spatial arrangement of groups about chiral centers in molecules
• Monosaccharides


  • Only those with 3 to 7 carbon atoms are commonly found in nature
• Triose


  Three-carbon monosaccharide
• Tetrose


  Four-carbon monosaccharide
• Pentose


  Five-carbon monosaccharide
• Hexose


  Six-carbon monosaccharide
• Aldose


  Monosaccharide that contains an aldehyde functional group
• Ketose


  Monosaccharide that contains a ketone functional group
• Monosaccharide classification


  • Aldoses
  • Ketoses
• Monosaccharides are often called sugars
• Hexoses


  Six-carbon sugars
• Pentoses


  Five-carbon sugars
• Saccharide


  From the Latin Saccharum, meaning sugar
• Aldoses in D configuration

  • Allose
  • Altrose
  • Glucose
  • Mannose
  • Gulose
  • Idose
  • Galactose
  • Talose
• Ketoses in D configuration

  • Psicose
  • Fructose
  • Sorbose
• The higher the number of chiral centers/carbons, the higher the possible number of optical isomers
• Epimers are carbohydrates that vary in one position for the placement of the -OH group
• Pyranose


  Cyclic monosaccharide containing a six-atom ring
• Furanose


  Cyclic monosaccharide containing a five-atom ring
• Anomeric carbon atom


  The hemiacetal carbon atom present in a cyclic monosaccharide structure
• Anomers


  The alpha and beta stereoisomers of cyclic monosaccharides that differ in the positions of the substituents on the anomeric carbon atom