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Mek

2018-10-24T16:09:19Z

170231211:

Mek, also known as MAP [[kinase]] kinase is part of the [[MAP Kinase Signalling Module]]. It is activated by [[Raf]] ([[MAP Kinase Kinase Kinase]]) by [[Phosphorylation]] as part of the [[Phosphorylation cascade]]. Once activated Mek then phosphorylates [[Erk]], which is the last MAP kinase molecule <ref>Alberts et al. (2008). Molecular biology of the cell. 5th edition. New York; Garland Science. 928-929</ref>.<br>

=== References ===

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Autophosphorylate

2018-10-24T16:06:49Z

170231211:

Autophosphorylation takes place in an Enzyme-Linked receptor called a Receptor Tyrosine Kinase (RTK). When the external domain of the receptor comes into contact with a signal it dimerises. This then triggers lots of phosphates to bind to the intracellular domain of the [[Receptor]] providing a docking site for other proteins. This is autophosphorylation. (Enzyme-Linked Receptors, [http://www.fastbleep.com/biology-notes/31/174/1000 http://www.fastbleep.com/biology-notes/31/174/1000], accessed on 22/11/13)

Allosteric site

2017-12-05T21:35:35Z

170231211: Created page with " Allosteric sites, are regions on an enzyme at which molecules bind too in order to denature said enzyme. These regions are found seperate and away from the active site of a..."

 Allosteric sites, are regions on an enzyme at which molecules bind too in order to denature said enzyme. These regions are found seperate and away from the active site of an enzyme and are often found on different polypeptide chains to the active site <ref>Biochemistry 5th edition. Berg JM, Tymoczko JL, Stryer L. Newyork. W.H. Freeman; 2000</ref>. They are disitnct regions of the polypeptide chain which certain inhibitor molecules are able to recognise and bind too. If an inhibitor molecule binds to an allosteric site then the enzyme undergoes a conformational change and the enzyme structure changes so therefore the active site shapee changes, thus meaning it cannot bind to its substrate. It is said to be denatured. the changes casued by allosteric binding are said to be final and irreversible <ref>Biochemistry 5th edition. Berg JM, Tymoczko JL, Stryer L. Newyork. W.H Freeman; 2000</ref> as any allosteric binding leads to an inability to form an enzyme substrate complex.

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Antiporter

2017-12-05T16:08:02Z

170231211: this image shows an antiporter in action moving sodium and hydrogen ions.

A transporter that uses the energy stored in the [[Electrochemical gradient|electrochemical gradient]] of one [[Solute|solute]] to drive the movement of another solute 'uphill' against its [[Electrochemical gradient|electrochemical gradient]]. The tight coupling of the transport of two different solutes allows the protein to harvest the [[Free energy|free energy]] released from the 'downhill' movement to power the movement of the other solute up its electrochemical gradient in the opposite direction<ref>Alberts et al.(2008)Molecular Biology of the Cell,5th Edition: p656</ref>. For example, the transport of [[Glucose|glucose]] against its concentration gradient can be coupled to the movement of [[Sodium|sodium]] [[Ions|ions]] down their [[Electrochemical gradient|electrochemical gradient]], where glucose moves in the opposite direction across the membrane to sodium<ref>Alberts et al.(2008)Molecular Biology of the Cell,5th Edition: p657, figure 11-9</ref>. [[Symporter|Also see symporter]].

=== [[Image:Antiporter image, wiki page.JPG|This image shows an antiporter moving sodium ions and protons across a cell membrane]]<ref>The cell: A molecular approach 2nd edition.Cooper GM. Sunderland (MA): Sinauer associates; 2000. Figure 12.33</ref> ===

References 

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File:Antiporter image, wiki page.JPG

2017-12-05T15:26:57Z

170231211: this image shows an anti-porter in action, moving sodium ions and protons in opposite directions via a transmembrane protein across a lipid bi-layer cell membrane.

this image shows an anti-porter in action, moving sodium ions and protons in opposite directions via a transmembrane protein across a lipid bi-layer cell membrane.