Integral and peripheral membrane proteins

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=== Integral Membrane Proteins  ===
 
=== Integral Membrane Proteins  ===
  
These are [[Protein|proteins]] directly linked to the [[Plasma membrane|plasma membrane]] of [[Cells|cells]]; they do not have intermediate [[Molecules|molecules]] between them and the [[Plasma membranes|plasma membranes]]. They are also considered as proteins that fully pass through the membrane ([[Carrier proteins|carrier proteins]] and [[Channel proteins|channel proteins]]).  
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These are [[Protein|proteins]] directly linked to the [[Plasma membrane|plasma membrane]] of [[Cells|cells]];&nbsp;they do not have intermediate [[Molecules|molecules]] between them and the [[Plasma membranes|plasma membranes]]. They are also considered as proteins that fully pass through the membrane ([[Carrier proteins|carrier proteins]] and [[Channel proteins|channel proteins]]). Transmembrane proteins can be single-pass, (pass through the membrane once), or mulitpass (pass through the membrane more than once). These transmembrane proteins have both [[Hydrophillic|hydrophilic]] and [[Hydrophobic|hydrophobic]] regions; they are amphiphilic<ref>Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2008) Molecular Biology of the Cell, 5th Edition, Pages 629-630, New York: Garland Science</ref>. The hydrophobic regions are the regions inside the lipid membrane, so they are kept away from water, whereas the hydrophilic regions are on either side of the membrane<ref>Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2008) Molecular Biology of the Cell, 5th Edition, Pages 630, New York: Garland Science</ref>. The hydrophobic regions interact with the hydrophobic tails on [[Phospholipid|lipids]] inside the membrane. The transmembrane domains are usually made up of [[Alpha-helix|alpha-helices]], although can be made up of [[Beta-sheet|beta-sheets]] rolled up into a [[Beta_Barrel|beta-barrell]].
  
They do not readily disocciate with the cell membrane, and&nbsp;can therefore only be separated from the plasma membrane through the&nbsp;use of detergents (and other agents) to disrupt the plasma membrane.
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They do not readily disocciate with the cell membrane, and&nbsp;can therefore only be separated from the plasma membrane through the&nbsp;use of detergents (and other agents) to disrupt the plasma membrane.  
  
 
=== Peripheral Membrane Proteins  ===
 
=== Peripheral Membrane Proteins  ===
  
These proteins are connected to the plasma membrane through intermediate [[Molecules|molecules]] (even integral proteins) by noncovalent interactions. They can be removed fro the membrane fairly easily by simply increasing the salt concentration of the buffer solution which the cells are suspended in.<br>
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These proteins are connected to the plasma membrane through intermediate [[Molecules|molecules]] (even integral proteins) by noncovalent interactions. They can be removed fro the membrane fairly easily by simply increasing the salt concentration of the buffer solution which the cells are suspended in.<br>
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=== References ===
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<references />

Revision as of 14:00, 23 October 2013

Integral Membrane Proteins

These are proteins directly linked to the plasma membrane of cells; they do not have intermediate molecules between them and the plasma membranes. They are also considered as proteins that fully pass through the membrane (carrier proteins and channel proteins). Transmembrane proteins can be single-pass, (pass through the membrane once), or mulitpass (pass through the membrane more than once). These transmembrane proteins have both hydrophilic and hydrophobic regions; they are amphiphilic[1]. The hydrophobic regions are the regions inside the lipid membrane, so they are kept away from water, whereas the hydrophilic regions are on either side of the membrane[2]. The hydrophobic regions interact with the hydrophobic tails on lipids inside the membrane. The transmembrane domains are usually made up of alpha-helices, although can be made up of beta-sheets rolled up into a beta-barrell.

They do not readily disocciate with the cell membrane, and can therefore only be separated from the plasma membrane through the use of detergents (and other agents) to disrupt the plasma membrane.

Peripheral Membrane Proteins

These proteins are connected to the plasma membrane through intermediate molecules (even integral proteins) by noncovalent interactions. They can be removed fro the membrane fairly easily by simply increasing the salt concentration of the buffer solution which the cells are suspended in.


References

  1. Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2008) Molecular Biology of the Cell, 5th Edition, Pages 629-630, New York: Garland Science
  2. Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2008) Molecular Biology of the Cell, 5th Edition, Pages 630, New York: Garland Science
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