Question

What are the differences between amphitrophic and peripherial proteins in the membrane and what functions do they have?

Answer 1

Peripheral membrane proteins do not cross the membrane but they can be attached to either side of the membrane or other proteins in the membrane. Peripheral membrane proteins have multiple functions including transportation to various locations in the cell, signaling, and maintaining the cell shape and structure.

amphitropic Having an affinity for both lipid and aqueous environments e.g. a membrane-associated protein that has domains that are embedded in the membrane and others that extend into the cytoplasm or the extracellular space.

The amphitropic category includes water-soluble channel-forming polypeptide toxins, which associate irreversibly with membranes but excludes peripheral proteins that interact with other membrane proteins rather than with lipid bilayer.

amphitropic proteins must interact strongly with the lipid bilayer in order to perform their biological functions, These include the enzymatic processing of lipids and other hydrophobic substances, membrane anchoring, and the binding and transfer of small nonpolar compounds between different cellular membranes.

peripheral membrane proteins are proteins involved in electron transport chains, such as cytochrome c, cupredoxins, high potential iron protein, adrenodoxin reductase, some flavoproteins, and others.

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