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Proteins/UNIPROT:Q9NY59
Catalyzes the hydrolysis of sphingomyelin to form ceramide and phosphocholine. Ceramide mediates numerous cellular functions, such as apoptosis and growth arrest, and is capable of regulating these 2 cellular events independently. Also hydrolyzes sphingosylphosphocholine. Regulates the cell cycle by acting as a growth suppressor in confluent cells. Probably acts as a regulator of postnatal development and participates in bone and dentin mineralization. Binds to anionic phospholipids (APLs) such as phosphatidylserine (PS) and phosphatidic acid (PA) that modulate enzymatic activity and subcellular location. May be involved in IL-1-beta-induced JNK activation in hepatocytes (By similarity). May act as a mediator in transcriptional regulation of NOS2/iNOS via the NF-kappa-B activation under inflammatory conditions (By similarity)..
Function from UniProtKB (Q9NY59), read 2026-09-23. CC BY 4.0.
Curated compounds routed: 0
41 statements
41 statements · 7 reference databases · Subject: SMPD3 · Sources: gene ontology, Hetionet, Human-GEM, Reactome, Rhea, UniProt, WikiPathways
13 reactions
water+a sphingomyelinan N-acylsphing-4-enine+proton+CHEBI:18132
Catalysed by SMPD3 or SMPD2 or SMPD4 or SMPD1 or ENPP7
Reaction pageLeft to rightBalance undeterminableEC 3.1.4.12cytosol
Human-GEM MAR00795CC BY 4.0Reference data
4 names
Resolves to: SMPD3
Reaction pageLeft to rightBalance undeterminableEC 3.1.4.12lysosome
Human-GEM MAR00797CC BY 4.0Reference data
water+a sphingomyelinan N-acylsphing-4-enine+proton+CHEBI:18132
Catalysed by SMPD3
Reaction pageLeft to rightBalance undeterminableEC 3.1.4.12Golgi apparatus
Human-GEM MAR08242CC BY 4.0Reference data
water+MAM02931cproton+CHEBI:18132+sphing-4-enine
Catalysed by SMPD3 or SMPD2 or SMPD4 or SMPD1 or ENPP7
Reaction pageLeft to rightBalancedEC 3.1.4.12cytosol
Human-GEM MAR08246CC BY 4.0Reference data
water+a sphingomyelinan N-acylsphing-4-enine+proton+CHEBI:18132
Catalysed by SMPD3
Reaction pageLeft to rightBalance undeterminableEC 3.1.4.12nucleus
Human-GEM MAR12086CC BY 4.0Reference data
a sphingomyelin+waterphosphocholine+an N-acylsphing-4-enine+hydron
Catalysed by SMPD2 or SMPD1 or ENPP7 or SMPD4 or SMPD3
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:19253CC BY 4.0Reference data
1-O-octadecyl-sn-glycero-3-phosphocholine+water1-O-octadecyl-sn-glycerol+phosphocholine+hydron
Reaction pageLeft to rightBalanced
Rhea RHEA:39923CC BY 4.0Reference data
1-hexadecanoyl-sn-glycero-3-phosphocholine+water1-hexadecanoyl-sn-glycerol+phosphocholine+hydron
Catalysed by SMPD2 or ENPP6 or ENPP7 or SMPD3
Reaction pageLeft to rightBalanced
Rhea RHEA:41119CC BY 4.0Reference data
a sphingosylphosphocholine+watera sphingoid base+phosphocholine+hydron
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:45296CC BY 4.0Reference data
an N-(acyl)-sphingosylphosphocholine+wateran N-acyl-sphingoid base+phosphocholine+hydron
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:45300CC BY 4.0Reference data
N-(15Z-tetracosenoyl)sphing-4-enine-1-phosphocholine+waterN-(15Z-tetracosenoyl)-sphing-4-enine+phosphocholine+hydron
Catalysed by SMPD3
Reaction pageLeft to rightBalanced
Rhea RHEA:45320CC BY 4.0Reference data
N-(tetracosanoyl)-sphing-4-enine-1-phosphocholine+waterN-tetracosanoyl-sphing-4-enine+phosphocholine+hydron
Catalysed by SMPD3
Reaction pageLeft to rightBalanced
Rhea RHEA:45324CC BY 4.0Reference data