Thekey difference在G蛋白连接的受体和酶连接受体之间G protein-linked receptors bind with an extracellular ligand and activate a membrane protein called a G-protein while enzyme-linked receptors bind with an extracellular ligand and cause enzymatic activity on the intracellular side.
In multicellular organisms, cells communicate with each other via chemical signals. Cells send messages as well as receive messages. Through these messages, all the activities occurring within the organism are coordinated.Paracrine,endocrine,自分泌, and direct signalling are the four major types of cell signalling mechanisms. Cells receive signals through receptors. These receptors can beintracellular receptors或者cell surface receptors. Intracellular receptors are present in the cytoplasm, while cell surface receptors are present on the exterior side of the cell membrane. There are three main types of cell surface receptors as ion channel linked receptors, G protein-linked receptors and enzyme-linked receptors.
1.Overview and Key Difference
2.What are G Protein Linked Receptors
3.What are Enzyme-Linked Receptors
4.Similarities Between G Protein Linked Receptors and Enzyme-Linked Receptors
5.Side by Side Comparison – G Protein Linked Receptors vs Enzyme-Linked Receptors in Tabular Form
What are G Protein Linked Receptors?
G蛋白连接受体是一种类型transmembrane proteins. As their name suggests, these receptors work with the G proteins that associate with GTP. GTP is a molecule like ATP that provides energy for G proteins to work. When a ligand binds with the G protein-linked receptor, it undergoes a conformational change in a way that it can interact with the G protein.
The inactive form of the G protein transforms into the active form and divides into two pieces (alpha and beta subunits) by converting GTP into GDP and utilizing the released energy. These subunits then separate from G protein-coupled receptor and interact with other proteins to trigger cell responses. Structurally, G protein-coupled receptors have seven transmembrane domains that span across the membrane.
What are Enzyme-Linked Receptors?
Receptor tyrosine kinase is an enzyme-linked receptor. It is a type of receptor protein involved in most of the cell signalling pathways. As its name implies, receptor tyrosine kinases are kinase enzymes. Kinase is an enzyme that catalyzes the transfer of phosphate groups to a substrate. These receptors contain tyrosine kinases that transfer a phosphate group from ATP to tyrosine.
What are the Similarities Between G Protein Linked Receptors and Enzyme-Linked Receptors?
- G protein-linked receptors and enzyme-linked receptors are two categories of cell surface receptors.
- They are transmembrane proteins.
- Initially, they remain inactive and then become active upon binding a ligand to the receptor.
G protein-linked receptors are the cell surface receptors that activate G proteins upon binding with an extracellular ligand. In contrast, enzyme-linked receptors are the cell surface receptors that activate with an enzyme and sets off a chain of events within the cell. So, this is the key difference between G protein-linked receptors and enzyme-linked receptors. Moreover, G protein-linked receptors have seven transmembrane domains spanning across the membrane while enzyme-linked receptors have a membrane-spanning a single alpha-helical region.
摘要 - G蛋白连接的受体与酶连接受体
1. “Signaling Molecules and Cellular Receptors.” Lumen,Available here.
1. “G protein” By Tpirojsi – Own work (Public Domain) viaCommons Wikimedia
2.“图09 01 07”CNX OpenStax–(CC BY 4.0)viaCommons Wikimedia