Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
lysosome | lysosomal phosphodiesterase acid SMase | Homo sapiens | 5764 | - |
plasma membrane | membrane-bound neutral SMase | Homo sapiens | 5886 | - |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required by N-SMase | Homo sapiens | |
Zn2+ | required by the secreted enzyme form | Homo sapiens |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
70000 | - |
x * 71000, N-SMase2, SDS-PAGE, x * 70000, mature A-SMase, SDS-PAGE, x * 75000, pre-pro-form of A-SMase, SDS-PAGE | Homo sapiens |
71000 | - |
x * 71000, N-SMase2, SDS-PAGE, x * 70000, mature A-SMase, SDS-PAGE, x * 75000, pre-pro-form of A-SMase, SDS-PAGE | Homo sapiens |
75000 | - |
x * 71000, N-SMase2, SDS-PAGE, x * 70000, mature A-SMase, SDS-PAGE, x * 75000, pre-pro-form of A-SMase, SDS-PAGE | Homo sapiens |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
a sphingomyelin + H2O | Homo sapiens | - |
a ceramide + choline phosphate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | - |
- |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
glycoprotein | the mature form and its precursors have six potential N-glycosylation sites, and at least five of them are important for proper folding, protection against proteolysis, and enzymatic activity of A-SMase. A-SMase has a mannose 6-phosphate residue that is required for lysosomal targetting of the enzyme via the mannose 6-phosphate receptor | Homo sapiens |
proteolytic modification | the 75-kDa pre-proform of A-SMase, which is a pre-polypeptide with little if any enzymatic activity in the endoplasmic reticulum, is cleaved to an intermediate pro-form of 72 kDa, and further to the mature enzyme of 70 kDa in the lysosomes | Homo sapiens |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
astrocyte | cortical astrocyte, acid SMase | Homo sapiens | - |
brain | brain-specific N-SMase2 | Homo sapiens | - |
microglia | acid SMase | Homo sapiens | - |
T-lymphocyte | - |
Homo sapiens | - |
U-937 cell | - |
Homo sapiens | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
a sphingomyelin + H2O | - |
Homo sapiens | a ceramide + choline phosphate | - |
? |
Subunits | Comment | Organism |
---|---|---|
? | x * 71000, N-SMase2, SDS-PAGE, x * 70000, mature A-SMase, SDS-PAGE, x * 75000, pre-pro-form of A-SMase, SDS-PAGE | Homo sapiens |
Synonyms | Comment | Organism |
---|---|---|
A-SMase | - |
Homo sapiens |
acid SMase | - |
Homo sapiens |
acid sphingomyelinase | - |
Homo sapiens |
N-SMase | - |
Homo sapiens |
neutral SMase | - |
Homo sapiens |
neutral sphingomyelinase | - |
Homo sapiens |
General Information | Comment | Organism |
---|---|---|
malfunction | deficiency of the enzyme leads to lysosomal accumulation of sphingomyelin resulting in in Niemann-Pick types A and B diseases | Homo sapiens |
metabolism | interaction in the NO/NOS and SMases/ceramide signaling pathways, overview | Homo sapiens |
additional information | from the gene of A-SMase, another product may be generated, i.e., the secretory SMase, which is very similar to A-SMase, differing only in the intracellular trafficking and in the need of zinc for activation | Homo sapiens |
physiological function | role for A-SMase in the release of plasma membrane-derived microparticles, overview A-SMase is a cation-independent hydrolase contributing to the catabolism of sphingomyelin in lysosomes. Stress is believed to activate A-SMase to generate ceramide, which serves as a cellular mediator in initiating apoptotic response, the process is controlled by NO, detailed overview. A-SMase activity is also crucial for developmental programmed cell death of oocytes. Modeling of A-SMase function in apoptosis, overview | Homo sapiens |