Sandbox Reserved 313: Difference between revisions
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=Introduction= | =Introduction= | ||
'''Sphingomyelin phosphodiesterase (Sphingomyelinase):''' (SMase) is an enzyme which catalyzes the hydrolysis of sphingomyelin (SM) to ceramide and phosphocholine. This enzyme also has hemolytic activity where red blood cells are ruptured and hemoglobin is released into the blood plasma. <ref name="gp">PMID: 16595670 </ref>. This enzyme has become the object of renewed interest since the discovery of the sphingomyelin [[signal transduction pathway]] which is involved in apoptosis. This pathway is initiated by a neutral sphingomyelinase hydrolysis of sphingomyelin in the plasma membrane to generate ceramide. Ceramide acts as a secondary messenger which causes the stimulation of the cascade effect of kinases and transcription factors which activate programmed cell death<ref name="gp2">PMID: 7544586 </ref>. | '''Sphingomyelin phosphodiesterase (Sphingomyelinase):''' (SMase) is an enzyme which catalyzes the hydrolysis of sphingomyelin (SM) to ceramide and phosphocholine. This enzyme also has hemolytic activity where red blood cells are ruptured and hemoglobin is released into the blood plasma. <ref name="gp">PMID: 16595670 </ref>. This enzyme has become the object of renewed interest since the discovery of the sphingomyelin [[signal transduction pathway]] which is involved in apoptosis. This pathway is initiated by a neutral sphingomyelinase hydrolysis of sphingomyelin in the plasma membrane to generate ceramide. Ceramide acts as a secondary messenger which causes the stimulation of the cascade effect of kinases and transcription factors which activate programmed cell death<ref name="gp2">PMID: 7544586 </ref>. | ||
== | ==Types of SMase<ref name="gp3">PMID: 12401200 </ref>:== | ||
''Acid sphingomyelinase (aSMase)'' - aSMase is a soluble lysosomal hydrolase with an optical acivity at pH 5. Acid-SMase has two enzymatic forms: one is targeted to the endo-lysosomal compartment where it coordinates Zn, and the other can be realeased extracellularly through the golgi secretory pathway<ref name="gp4">PMID: 21098024 </ref>. A deficiency in results in the lysosomal storage disorder Niemann-Pick disease. Acid-SMase normally metabolizes sphingomyelin which is found in every cell of the body. When aSMase is lacking in the cell, SM builds up and eventually results in cell death<ref name="gp5">PMID: 18567738 </ref>. | ''Acid sphingomyelinase (aSMase)'' - aSMase is a soluble lysosomal hydrolase with an optical acivity at pH 5. Acid-SMase has two enzymatic forms: one is targeted to the endo-lysosomal compartment where it coordinates Zn, and the other can be realeased extracellularly through the golgi secretory pathway<ref name="gp4">PMID: 21098024 </ref>. A deficiency in results in the lysosomal storage disorder Niemann-Pick disease. Acid-SMase normally metabolizes sphingomyelin which is found in every cell of the body. When aSMase is lacking in the cell, SM builds up and eventually results in cell death<ref name="gp5">PMID: 18567738 </ref>. | ||