A novel magnesium-independent neutral sphingomyelinase associated with rat central nervous system meylin.
Purified myelin fractions prepared from young adult rat brain contain a novel sphingomyelinase which has a pH optimum of 7.0 and does not require divalent cations. This sphingomyelinase is different from the two previously known sphingomyelinases in the brain--the acidic sphingomyelinase and the magnesium-dependent neutral sphingomyelinase. When the distributions of the sphingomyelinases among the purified myelin, the total subcellular fractions heavier than myelin (greater than 0.85 M sucrose), and the microsomes were examined, the magnesium-independent sphingomyelinase was detected only in myelin, while the magnesium-dependent sphingomyelinase was present in the other two fractions but not in myelin. Therefore, this new sphingomyelinase appears to be specifically localized in the myelin sheath.
D000818:Animals; D001921:Brain / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D009186:Myelin Sheath / Q000201:enzymology*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D051381:Rats; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism*
D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase; D008274:Magnesium