Cyclic AMP (cAMP) is a crucial second messenger in cellular signaling, regulating metabolism and gene expression. It is synthesized from ATP and activates protein kinase A (PKA), influencing metabolic pathways. In prokaryotes, cAMP controls gene expression, notably in the lac operon, linking nutrient availability to genetic activity. Understanding cAMP's synthesis, structure, and function is key to comprehending cellular responses to stimuli.
Show More
cAMP is a second messenger that plays a crucial role in cellular signal transduction
Comparison to ATP and AMP
The cyclic structure of cAMP distinguishes it from ATP and AMP, which have linear phosphate groups
cAMP is formed from ATP by the enzyme adenylyl cyclase, which catalyzes the formation of a cyclic bond between the remaining phosphate and the ribose sugar
cAMP mediates intracellular communication and regulates various metabolic pathways by activating protein kinase A (PKA)
Glycogen, Sugar, and Lipid Metabolism
cAMP plays a key role in regulating the metabolism of glycogen, sugars, and lipids through the activation of PKA
cAMP is involved in the signaling pathways of both eukaryotic and prokaryotic cells, along with other second messengers like cGMP, IP3, DAG, and Ca2+
cAMP production is initiated by the activation of adenylyl cyclase, which is stimulated by G-proteins in response to extracellular signals
cAMP is deactivated by phosphodiesterase enzymes, which hydrolyze the cyclic bond in cAMP, converting it to AMP
The lac Operon
In prokaryotic cells, cAMP is crucial for regulating gene expression, particularly in the lac operon, which controls the metabolism of lactose
The concentration of cAMP in bacterial cells is inversely related to the availability of glucose, and high cAMP levels promote the activation of the lac operon to utilize alternative sugar sources like lactose
00
Second messenger definition
Molecule that relays signals received at receptors on the cell surface to target molecules inside the cell.
01
Difference between eukaryotic and prokaryotic cells
Eukaryotic cells have a nucleus and membrane-bound organelles; prokaryotic cells do not.
02
Examples of second messengers besides cAMP
cGMP, IP3, DAG, and Ca2+ are other second messengers in cellular signal transduction.
