Protein Function

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Protein Function

• March 27th, 2009

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Proteins

• The most versatile macromolecules in living
  systems, serving crucial functions in essentially
  all biological processes.

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Structural Role of Proteins

• Structural proteins are fibrous and stringy
• Examples keratin, collagen, and elastin.
• Keratins strengthen protective coverings such as
  hair, feathers, horns, and beaks.
• Collagens and elastin provide support for
  connective tissues such as tendons and ligaments.
• Cytoskeleton
• Contractile proteins structure allows for
  movement

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Immuno-roles of Proteins

• Some proteins are specialized to play the role of
  antibodies
• Antibodies defend the body against foreign
  invaders (like bacteria and viruses) by binding
  them and targeting them for destruction.

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Maintaining Fluid Balance

• The presence of blood protein molecules, such as
  albumins and globulins, are critical factors in
  maintaining the proper fluid balance between
  cells and extra cellular space.
• If proteins werent present, body fluids couldnt
  be pulled out of tissues and swelling would
  result.

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Providing Energy - Gluconeogenesis

• Proteins are last on the list of macronutrients
  to be used for energy, though they can provide it
• Glucose for cellular respiration can be produced
  from some amino acids if needed during times of
  fasting.

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Acid-Base Balance

• Certain proteins, particularly hemoglobin, help
  maintain the pH of the body by picking up H
  ions that are produced during other biochemical
  processes
• Certain proteins, particularly albumin, help
  maintain the pH of the body by adding H ions to
  body fluid
• These pH balancers are called buffers because
  they buffer body fluids from changes in pH

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Proteins with Transport Functions

• Carrier proteins which move molecules from one
  place to another around the body. Examples
  include hemoglobin and cytochromes.
• Hemoglobin transports oxygen through the blood.
• Cytochromes operate in the electron transport
  chain as electron carrier proteins.

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