macromolecule transmembrane transporter activity
Definition
Target type: molecularfunction
Enables the transfer of a macromolecule from one side of a membrane to the other. [GOC:mtg_transport, ISBN:0815340729]
Transmembrane transporter activity encompasses the movement of molecules across biological membranes, a fundamental process for cellular life. These molecules can include ions, sugars, amino acids, lipids, and even larger macromolecules like proteins. The key feature of transmembrane transporters is their ability to facilitate the passage of specific molecules, often against their concentration gradients, requiring energy expenditure. This selectivity and directed movement play crucial roles in maintaining cellular homeostasis, nutrient uptake, waste removal, signal transduction, and many other vital processes.
Transmembrane transporters can be classified into different families based on their structure, mechanism, and substrate specificity. Some prominent examples include:
* **Channel proteins:** These proteins form pores through the membrane, allowing passive diffusion of molecules down their concentration gradients. Examples include ion channels that regulate the flow of ions across the membrane, contributing to electrical signaling in neurons and muscle cells.
* **Carrier proteins:** These proteins bind to specific molecules and undergo conformational changes to transport them across the membrane. This process can be either passive, driven by the concentration gradient, or active, requiring energy expenditure. Active transporters use energy sources like ATP or ion gradients to move molecules against their concentration gradients.
* **Pumps:** These are a specialized type of carrier protein that actively transport molecules against their concentration gradients, often using ATP as an energy source. Examples include sodium-potassium pumps, which maintain the electrochemical gradient across the plasma membrane, essential for nerve impulse propagation and muscle contraction.
The molecular function of transmembrane transporter activity is complex and multifaceted, involving intricate interactions between the transporter protein, the transported molecule, and the membrane environment. Understanding these interactions is crucial for developing therapies targeting various diseases, including cancer, neurological disorders, and infectious diseases.'
"
Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Multidrug resistance-associated protein 5 | An ATP-binding cassette sub-family C member 5 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O15440] | Homo sapiens (human) |
Compounds (7)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| dilazep | dilazep : A member of the class of diazepanes that is 1,4-diazepane substituted by 3-[(3,4,5-trimethoxybenzoyl)oxy]propyl groups at positions 1 and 4. It is a potent adenosine uptake inhibitor that exhibits antiplatelet, antianginal and vasodilator properties. Dilazep: Coronary vasodilator with some antiarrhythmic activity. | benzoate ester; diazepane; diester; methoxybenzenes | cardioprotective agent; platelet aggregation inhibitor; vasodilator agent |
| dipyridamole | dipyridamole : A pyrimidopyrimidine that is 2,2',2'',2'''-(pyrimido[5,4-d]pyrimidine-2,6-diyldinitrilo)tetraethanol substituted by piperidin-1-yl groups at positions 4 and 8 respectively. A vasodilator agent, it inhibits the formation of blood clots. Dipyridamole: A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752) | piperidines; pyrimidopyrimidine; tertiary amino compound; tetrol | adenosine phosphodiesterase inhibitor; EC 3.5.4.4 (adenosine deaminase) inhibitor; platelet aggregation inhibitor; vasodilator agent |
| sulfinpyrazone | Sulfinpyrazone: A uricosuric drug that is used to reduce the serum urate levels in gout therapy. It lacks anti-inflammatory, analgesic, and diuretic properties. | pyrazolidines; sulfoxide | uricosuric drug |
| trequinsin | trequinsin: RN given refers to parent cpd; structure given in first source | pyridopyrimidine | |
| l 660,711 | quinolines | ||
| cyclic gmp | 3',5'-cyclic GMP : A 3',5'-cyclic purine nucleotide in which the purine nucleobase is specified as guanidine. Cyclic GMP: Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed) | 3',5'-cyclic purine nucleotide; guanyl ribonucleotide | Escherichia coli metabolite; human metabolite; mouse metabolite; plant metabolite; Saccharomyces cerevisiae metabolite |
| sildenafil | sildenafil : A pyrazolo[4,3-d]pyrimidin-7-one having a methyl substituent at the 1-position, a propyl substituent at the 3-position and a 2-ethoxy-5-[(4-methylpiperazin-1-yl)sulfonyl]phenyl group at the 5-position. | piperazines; pyrazolopyrimidine; sulfonamide | EC 3.1.4.35 (3',5'-cyclic-GMP phosphodiesterase) inhibitor; vasodilator agent |