▁an ▁en zym e ▁primarily ▁present ▁in ▁pl asma ▁memb rane , ▁will ▁convert ▁cer am ide ▁to ▁s ph ing os ine . ▁s ph ing os ine ▁is ▁then ▁ph osph ory l ated ▁by ▁s ph ing os ine ▁kin ase ▁( SK ) ▁is o enz ym es . ▁ ▁There ▁are ▁two ▁identified ▁is o enz ym es , ▁SK 1 ▁and ▁SK 2 . ▁These ▁two ▁en zym es ▁have ▁different ▁t issue ▁distribution . ▁SK 1 ▁is ▁highly ▁expressed ▁in ▁s ple en , ▁lung ▁and ▁le uk ocy tes . ▁While , ▁SK 2 ▁is ▁highly ▁expressed ▁in ▁li ver ▁and ▁kid ney . ▁SK 2 ▁is ▁located ▁mainly ▁in ▁the ▁mit och ond ria , ▁nucle us ▁and ▁the ▁end op las mic ▁ret icul um ▁whereas ▁SK 1 ▁is ▁mainly ▁located ▁in ▁cy top las m ▁and ▁the ▁cell ▁memb rane . ▁ ▁Met abol ism ▁and ▁de grad ation ▁S 1 P ▁can ▁be ▁de ph osph ory l ated ▁to ▁s ph ing os ine ▁by ▁s ph ing os ine ▁ph osph at ases ▁and ▁can ▁be ▁irre vers ibly ▁de grad ed ▁by ▁an ▁en zym e , ▁s ph ing os ine ▁ph osph ate ▁ly ase . ▁ ▁Function ▁S 1 P ▁is ▁a ▁blood ▁bor ne ▁li pid ▁medi ator , ▁in ▁particular ▁in ▁association ▁with ▁li pop rote ins ▁such ▁as ▁high ▁density ▁li pop rote in ▁( H DL ). ▁It ▁is ▁less ▁abund