An Mn2+-stimulated neutral-sphingomyelinase in seminiferous tubules of immature Wistar rats

Mammalian sphingomyelinases have been implicated in many important physiological and pathophysiological processes. The seminiferous tubules of immature (19 day-old) Wistar rats have at least three types of sphingomyelinases, a lysosomal one and two microsomal ones. One of the microsomal sphingomyeli...

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Bibliographic Details
Published in:Molecular and cellular biochemistry 1999-11, Vol.201 (1-2), p.125-129
Main Authors: Raimann, P E, Custodio de Souza, I C, Bernard, E A, Guma, F C
Format: Article
Language:English
Subjects:
Age Factors
Animals
Hydrogen-Ion Concentration
Hydrolysis
Magnesium - pharmacology
Male
Manganese - pharmacology
Metals - pharmacology
Microsomes - drug effects
Microsomes - enzymology
Rats
Rats, Wistar
Rodents
Seminiferous Tubules - drug effects
Seminiferous Tubules - enzymology
Sphingomyelin Phosphodiesterase - drug effects
Sphingomyelin Phosphodiesterase - metabolism
Sphingomyelins - metabolism
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Summary:Mammalian sphingomyelinases have been implicated in many important physiological and pathophysiological processes. The seminiferous tubules of immature (19 day-old) Wistar rats have at least three types of sphingomyelinases, a lysosomal one and two microsomal ones. One of the microsomal sphingomyelinases is active at pH 6.5 and is stimulated by Mn2+ > Co2+ > Mg2+, and the other is active at pH 7.4 and is stimulated by Mn2+ > Mg2+ and inhibited by Co2+. The two microsomal enzymes are only slightly inhibited by EDTA and at pH 7.4 the stimulatory effects of Mn2+ and Mg2+ are additive. These data characterize the existence of two different membrane-bound sphingomyelinases in the seminiferous tubules of the rat.
ISSN:0300-8177
1573-4919
DOI:10.1023/A:1007046024246