Sphingomyelin phosphodiesterase
（重定向自Sphingomyelinase）
A third N-SMase protein - termed nSMase3 - was recently cloned and characterized. nSMase3 bears little sequence similarity to either nSMase1 or nSMase2. However, there appears to be a high degree of evolutionary conservation from lower to higher organisms suggesting that it may comprise a unique and distinct N-SMase. The high expression of nSMase3 in heart and skeletal muscle also suggests potential roles in heart function.