lumenal side of lysosomal membrane
Definition
Target type: cellularcomponent
The side (leaflet) of the lysosomal membrane that faces the lumen. [GOC:dos]
The luminal side of the lysosomal membrane faces the lumen of the lysosome, a compartment filled with acidic hydrolytic enzymes that are responsible for the degradation of macromolecules. This side of the membrane is characterized by a unique lipid composition compared to other cellular membranes, enriched in phosphoinositides and cholesterol. It also harbors specific transmembrane proteins that play crucial roles in lysosomal function. These proteins include:
- **Lysosomal transmembrane proteins:** These proteins serve as receptors for the delivery of substrates to the lysosome for degradation. They often bind to specific ligands, such as mannose-6-phosphate receptors, which facilitate the transport of newly synthesized lysosomal enzymes from the Golgi apparatus.
- **Proton pumps (V-ATPases):** These pumps actively transport protons into the lysosomal lumen, maintaining its acidic pH, which is essential for the optimal activity of the hydrolytic enzymes.
- **Membrane transporters:** These proteins facilitate the transport of ions, metabolites, and other molecules across the lysosomal membrane, regulating the internal environment of the lysosome and ensuring proper functioning of the degradative processes.
- **Lipid modifying enzymes:** These enzymes contribute to the unique lipid composition of the lysosomal membrane, including the synthesis and degradation of specific phospholipids and cholesterol.
The luminal side of the lysosomal membrane also interacts with the luminal contents, including the degraded products of macromolecules. The membrane itself is resistant to the hydrolytic activity of the lysosomal enzymes, preventing the destruction of the lysosome itself. This stability is crucial for the long-term function of the lysosome and its role in cellular homeostasis.'
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Proteins (2)
| Protein | Definition | Taxonomy |
|---|---|---|
| Heat shock cognate 71 kDa protein | A heat shock cognate 71 kDa protein that is encoded in the genome of human. [PRO:DAN] | Homo sapiens (human) |
| Lysosomal protective protein | A lysosomal protective protein that is encoded in the genome of human. [PRO:DNx, UniProtKB:P10619] | Homo sapiens (human) |
Compounds (16)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 3,4-dichloroisocoumarin | 3,4-dichloroisocoumarin : A member of the class of isocoumarins that is isocoumarin substituted by chloro groups at positions 3 and 4. It is a serine protease inhibitor. | isocoumarins; organochlorine compound | geroprotector; serine protease inhibitor |
| isoflurophate | Isoflurophate: A di-isopropyl-fluorophosphate which is an irreversible cholinesterase inhibitor used to investigate the NERVOUS SYSTEM. | dialkyl phosphate | |
| adenosine diphosphate | Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position. | adenosine 5'-phosphate; purine ribonucleoside 5'-diphosphate | fundamental metabolite; human metabolite |
| tubercidin | tubercidin : An N-glycosylpyrrolopyrimidine that is adenosine in which the in the 5-membered ring that is not attached to the ribose moiety is replaced by a carbon. Tubercidin is produced in the culture broth of Streptomyces tubericidus. Tubercidin: An antibiotic purine ribonucleoside that readily substitutes for adenosine in the biological system, but its incorporation into DNA and RNA has an inhibitory effect on the metabolism of these nucleic acids. | antibiotic antifungal agent; N-glycosylpyrrolopyrimidine; ribonucleoside | antimetabolite; antineoplastic agent; bacterial metabolite |
| toyocamycin | toyocamycin : An N-glycosylpyrrolopyrimidine that is tubercidin in which the hydrogen at position 5 of the pyrrolopyrimidine moiety has been replaced by a cyano group. Toyocamycin: 4-Amino-5-cyano-7-(D-ribofuranosyl)-7H- pyrrolo(2,3-d)pyrimidine. Antibiotic antimetabolite isolated from Streptomyces toyocaensis cultures. It is an analog of adenosine, blocks RNA synthesis and ribosome function, and is used mainly as a tool in biochemistry. | antibiotic antifungal agent; N-glycosylpyrrolopyrimidine; nitrile; ribonucleoside | antimetabolite; antineoplastic agent; apoptosis inducer; bacterial metabolite |
| nsc 65346 | sangivamycin : A nucleoside analogue that is adenosine in which the nitrogen at position 7 is replaced by a carbamoyl-substituted carbon. It is a potent inhibitor of protein kinase C. sangivamycin: RN given refers to parent cpd | nucleoside analogue | protein kinase inhibitor |
| adenosine | quinquefolan B: isolated from roots of Panax quinquefolium L.; RN not in Chemline 10/87; RN from Toxlit | adenosines; purines D-ribonucleoside | analgesic; anti-arrhythmia drug; fundamental metabolite; human metabolite; vasodilator agent |
| 8-aminoadenosine | |||
| e 64 | E 64: cysteine protease inhibitor of microbial origin, which inhibits cathepsin B (EC 3.4.22.1) and cathepsin L (EC 3.4.22.-) | dicarboxylic acid monoamide; epoxy monocarboxylic acid; guanidines; L-leucine derivative; zwitterion | antimalarial; antiparasitic agent; protease inhibitor |
| bortezomib | amino acid amide; L-phenylalanine derivative; pyrazines | antineoplastic agent; antiprotozoal drug; protease inhibitor; proteasome inhibitor | |
| 5'-deoxyadenosine | 5'-deoxyadenosine : A 5'-deoxyribonucleoside compound having adenosine as the nucleobase. 5'-deoxyadenosine: main heading DEOXYADENOSINE refers to the 3' cpd | 5'-deoxyribonucleoside; adenosines | Escherichia coli metabolite; human metabolite; mouse metabolite |
| gs-7340 | tenofovir alafenamide : An L-alanine derivative that is isopropyl L-alaninate in which one of the amino hydrogens is replaced by an (S)-({[(2R)-1-(6-amino-9H-purin-9-yl)propan-2-yl]oxy}methyl)(phenoxy)phosphoryl group. A prodrug for tenofovir, it is used (as the fumarate salt) in combination therapy for the treatment of HIV-1 infection. tenofovir alafenamide: component of Biktarvy | 6-aminopurines; ether; isopropyl ester; L-alanine derivative; phosphoramidate ester | antiviral drug; HIV-1 reverse transcriptase inhibitor; prodrug |
| carfilzomib | epoxide; morpholines; tetrapeptide | antineoplastic agent; proteasome inhibitor | |
| ver 155008 | VER 155008: structure in first source | purine nucleoside | |
| rpx7009 | RPX7009: a beta-lactamase inhibitor; structure in first source | ||
| nms-e973 | NMS-E973: structure in first source |