Proteins

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Proteins

• Jitka Škopová a Lenka Šibravová

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Protein (from the Greek "protas" meaning "of
primary importance )

• one of the classes of bio-macromolecules
  (alongside polysaccharides, lipids, and nucleic
  acids)
• discovered by Jöns Jakob Berzelius (Swedish
  chemist) in 1838
• discovered lithium, vanadium, silicon, selenium,
  thorium, and cerium)

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Proteins characteristics

• complex, high-molecular-weight organic compound
• consists of amino acids joined by peptide bonds
• proteins are polymers, with amino acids being the
  monomers
• one of the classes of bio-macromolecules
• function of all living cells and viruses

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Proteins structure
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Biochemists refer to four distinct aspects of a
protein's structure

• Primary structure
• the amino acid sequence (the order in which the
  amino acids are linked together (specified by
  genetic information)
• Secondary structure
• consists of several repeating patterns in a part
  of polypeptide chain
• contain a-helix and ß-pleated sheet

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• Tertiary structure
• the overall shape of a single
• protein molecule
• hydrophobic interactions
• hydrogen bonds
• disulfide bonds
• Quaternary structure
• composed of several polypeptide chains subunits
  
• noncovalent
• hydrophobic interactions
• salt bridges
• H-bonds
• covalent
• (S-S) forces

Three-dimensional structure of myoglobine
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Functions

• many proteins are enzymes, catalyzing chemical
  reactions
• regulation of cellular functions
• signal transduction
• metabolism
• control almost all the molecular processes of the
  body
• those molecules that do everything that happens
  within us
• proteases
• glycosidases

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Occurence

• in the body
• keratin, collagen, elastin and silk fibroin,
  blood, muscle
• in food
• egg, milk, cheese
• plant, animal, microbial

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• compound sloucenina
• joined spojený
• essential nezbytný
• polypeptide chain polypeptidické retezce
• hydrogen bonds vodíkové mustky
• occurence výskyt
• salt bridges sodné mustky

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