What is the Difference Between Transmembrane and Peripheral Proteins?

Transmembrane and peripheral proteins are two types of membrane proteins that play different roles in cellular function. The main differences between them are their association with the lipid bilayer, their function, and their structure.

1. Association with the lipid bilayer: Transmembrane proteins have one or more helices that pass through the lipid bilayer, making them integral membrane proteins. In contrast, peripheral proteins are more loosely attached to the inside and outside surfaces of the lipid bilayer and are not considered integral proteins.
2. Function: Transmembrane proteins often function on both sides of the bilayer or transport molecules across the membrane. They are involved in cell signaling and can be associated with ion channels and transmembrane receptors. Peripheral proteins, on the other hand, are involved in cell shape maintenance and support the cell membrane to maintain its structure.
3. Structure: Transmembrane proteins have hydrophobic domains that arrange in alpha helices, allowing them to be embedded within the lipid bilayer. Peripheral proteins can be attached to integral membrane proteins or can stick into a small portion of the lipid bilayer by themselves. Most peripheral membrane proteins are hydrophilic.

Comparative Table: Transmembrane vs Peripheral Proteins

Transmembrane and peripheral proteins are two types of membrane proteins that have different structures and functions. Here is a table summarizing their differences:

Transmembrane proteins have hydrophobic domains that arrange in alpha helices, allowing them to extend across the entire membrane. They are a type of integral proteins and are involved in cell signaling. Peripheral proteins, on the other hand, are not integral proteins and are only temporarily or loosely attached to the membrane. They play a role in maintaining cell shape and supporting the cell membrane structure.