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Stearyl-alcohol biosynthesis from stearyl-CoA in mouse brain microsomes in normal and dysmyelinating mutants (quaking and jimpy)
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Severfl studies in ~ v o [2,13,14] and in vitro[lO] have s h o r t that fat,gy
226
~or these phospholipids are concentrated in myelin membrane [16]. Therefore, studies were also undertaken in the Qualdng and Jimpy dysmyelinating mutant mice: illthese animals no data have been presen~d on fattyalcohol biosynthesis. C57BI/6J mice and Jimpy and Quaking mutant mice are raisedin our laboratory. Microsomal preparations from 18
:
acid 50:30.20 (v/v/v ),B e Rf v~ues for ste~c acid, ste~l-CoA
R E S U L T S A N D DISCUSSION
:227
C o A are,
:
~t-
will beus~, since adding N ~ H in the presence of N ~ P H does not significantly change the synthesis. When using stearic acid, ATP, CoA and M~:2÷ insteac of s t e ~ l ~ o A , the yield of fatty alcohol synthems is r e d u c ~ b y 60% (as fatty acid rnust be activated and then reduced ~ m two steps ~action probably reduces the yield), In the abmnce of A T P the yield of fat~, alcohol synthesis is nil.The rate of formation of stearyl-alcoholis found robe nearly linear up to 1 m g protein; under the conditions described, it is also linearup to 30 rain of
/0
~ . ~ _.--~-~_.__ 0 plasmalogen
. . . . . . . .
corltent
,,OOlo
syntllesize~
2,
//.
/
T
,A
luring brain developmenL 0,
228
incdbation. A minute amount of fatty aldehyde is detected. Thus, there is no conclusive evidence l;or the formation of fatty aldehyde as an intermediate as h~s been proposed [)~1]. From these studies the conversion of stearic acid to stearyl-alcohol in meuse brain may be envisaged as: s~earic acid
CoA
-~ stearyl-CoA ~ ATP Mg
stearyl-alcohol
This confirm the results obtained in rat brain where palmitic acid is transformed into hexadecanol in the presence of CoA and ATP [11]. This pathway of reduction of activated fatty acid is probably universal since several studies indicate that fatty acids are good precursors of ether-linked long chain moieties in glycerolipids in various biological systems. However, this pathway does not exclude tha~; fatty alcohols could be formed by oxidation of hydrocarbons, as these compounds have been recently detected in brain [ 6]. In Fig. 1 is shown the plasmalogen content in the normal brain as a function i
n moles stearyl a~ohol
T N []
N ~r
1o{
| ]L
Qk
Qk
l
]p
I i
Jp
]
i
mg proteins
total activity ~er brain in vitro
Fig. '2. Stearyl-alcohol biosynthesis iv normal and dysrnyelinating mutants (Quaking and J~mpy). N, normal; Qk, Quaking; Jp, Jimpy.
229
of age. The highest speed of deposition is around 15 days of age (between 12 and 20 days); very young animals (3-day-old) contain 18% of the adult !eve]. In the adult the values are 14.9 -+ 0.9 pmole/g vrain, or 6.1 _+ 0.6.pmo]e/br~no in Quaking these values are, respectively, 9.1 + 0.8 and 3.6 -+ 0.5. This curve is similar to the one obtained in the rat [16]. Steary]-alcohol biosynthesis is maximal at 15 days and slowlydecreases thereafter. This unexpected light decrease is probably due to the occurrence of plasmalogens beside myelin and to a greater turn-over of plasmalogens than other myelin ]ipids. In Fig. 2 is shown stearyl-alcohol biosynthesis in 18
This work was supported by I.N.S.E.R.M. (C.L. No 75.1. 196.6). The authors ~re grateful to Professor Ailhaud for judicious advice during acyi-CoA synthesis wad to F. Lachapeile and A. De Almeida for breeding the anima]s. REFERENCES 1. Baumaun, N.A., Jacque, C., Pollet, S. and H~pin, M.L., Fatty acid and lipid composition of the brmn of a myelin deficient mutant, the Quaking mouse, Europ..J. Biochem., 4 (1968) 3 4 ~ 3 4 4 , 2 Bell,O'Ei, Blank, M.L. and Snyder, F., The incorporation of ~ O and ~4C from long chain alcohols into the ~dkyl and alk-l-enylethers of phospholipids of developing brain, Biochim! biophys. Acta (Amst,), 231 (1970) 577--593. 3 Bourre, JIM,, Poller,S.A., Dubois, G. et Baumann, N.A., Biosynthdse des acides gras trds longues cha~hes dans les micrOsomes de cerveau de souris,C.R. Acad. Sci. (Paris), 271 (1970) 1221--1223. 4 Bourre~ J.i~I.,Po|let,S.A., Daudu, O.L. and Baumanr~, N.A., Evoh~tion in mouse brmn microsomes of lipidsand their constituents during myelination, Brain Res., 51 (1973) 225--239i 5 Bour~ Daudu, O~L, and B~umann~ N.A., Lignocericacid in the developing brain. Activities of mitochondri~ ace~l-CoA dependent synthesis and microsom~ ma]onyl system in relation to myelination, Europ: J. Biochem°, 72 (!977) .
4i~,47i
.
.
.
230
6 Bourre, J.M,, C~ss~ne: C., Larrouquere-Re~nier, S. and Daffier, D., Occurrence of ~dkane in brain myelin. Co mpariron between normal and Quaking mouse, J. N~urochem., 29 (1977) 645--648. 7 Dorzr~an,R.V., Freysz, L. and Morrocks, L.A., Synthesis of ethanolamine phosphoglycerides by microsomes from the brains of Jimpy and Quaking mice, J. Neurochem., 29 (197~') 231--233. 8 Goldman, P. and Vagelos, R., Chemic~ synthesis or acyl C o A esters,J. biol. Chem., 236 (1961) 2620--2629. 9 Gottfried,E.L. and Rapport~ Id.M., The biochemistry of plasmalogens, J. biol. chem., 237 (1962) 329--333. 10 Hajra,A.K. Biosynthesis of alk~.'l~thercontaining lipid from dihydro~yacetc~ne phosphate, Biochem. Biophys. Res. Commun., 164 (1969) 486-492. 11 Natraj~r~Y. and S~try, P.S.,Conversion of (1-14C)palmiticacid to (1-14C)hexadecanol by developing rat brain cellfree preparation, J. Neurochem., 26 (I '976) 107--113. 12 Paturneau~Jou~s, M.~ Baumann, N. and Bourre, J.M., Elongatioy, of p~Imityl-CoA in mouse brain mitochondria. Comparison with stearyl-CoA, Bioc~em. Biophys. Res. Commun., 4 (1976) 1326--1334. 13 Schmid, H.H. and Tak~ashi, T., Reductive and oxidative bio~'ntbesis of plasmalogens in myelinating brain J. biol.Chem., 11 (1970) 412--419. 14 Stoff~|~'W. and Lekim, D., On the stereospecificityof the bJJchemical dehydrogenation of the 1-O-alkylglyceryl to the 1-O-alk-l'-enylglyceryl ether bond, Hoppe-Seyler~s Z. Physiol. Chem., 352 (1971) 501--511. 15 Takahashi, T. and Schmid, T., Long chain alcohorin mammalian tissue,Chem. Phys. Lipids, ~ (1970) 243--246. 16 Wells,M.A. and Dittmer, J.C., A comprehensive study of the postnatal changes in the concentration of the lipidsof developing rat brain,biochemistry, 6 (1967) 3169--3175.
7
~d~,iill
ii/¸i i~/i!¸//! ,,,•
i¸
•
~iil ~~ iJ!!iill ¸¸¸! i/i~i ii i¸¸ i~ •
•
,,
.
.
.
.
.
.
~~ ~ .
.
.
.
~ !
~
.... • •
•
•
•
•
Severfl studies in ~ v o [2,13,14] and in vitro[lO] have s h o r t that fat,gy
226
~or these phospholipids are concentrated in myelin membrane [16]. Therefore, studies were also undertaken in the Qualdng and Jimpy dysmyelinating mutant mice: illthese animals no data have been presen~d on fattyalcohol biosynthesis. C57BI/6J mice and Jimpy and Quaking mutant mice are raisedin our laboratory. Microsomal preparations from 18
:
acid 50:30.20 (v/v/v ),B e Rf v~ues for ste~c acid, ste~l-CoA
R E S U L T S A N D DISCUSSION
:227
C o A are,
:
~t-
will beus~, since adding N ~ H in the presence of N ~ P H does not significantly change the synthesis. When using stearic acid, ATP, CoA and M~:2÷ insteac of s t e ~ l ~ o A , the yield of fatty alcohol synthems is r e d u c ~ b y 60% (as fatty acid rnust be activated and then reduced ~ m two steps ~action probably reduces the yield), In the abmnce of A T P the yield of fat~, alcohol synthesis is nil.The rate of formation of stearyl-alcoholis found robe nearly linear up to 1 m g protein; under the conditions described, it is also linearup to 30 rain of
/0
~ . ~ _.--~-~_.__ 0 plasmalogen
. . . . . . . .
corltent
,,OOlo
syntllesize~
2,
//.
/
T
,A
luring brain developmenL 0,
228
incdbation. A minute amount of fatty aldehyde is detected. Thus, there is no conclusive evidence l;or the formation of fatty aldehyde as an intermediate as h~s been proposed [)~1]. From these studies the conversion of stearic acid to stearyl-alcohol in meuse brain may be envisaged as: s~earic acid
CoA
-~ stearyl-CoA ~ ATP Mg
stearyl-alcohol
This confirm the results obtained in rat brain where palmitic acid is transformed into hexadecanol in the presence of CoA and ATP [11]. This pathway of reduction of activated fatty acid is probably universal since several studies indicate that fatty acids are good precursors of ether-linked long chain moieties in glycerolipids in various biological systems. However, this pathway does not exclude tha~; fatty alcohols could be formed by oxidation of hydrocarbons, as these compounds have been recently detected in brain [ 6]. In Fig. 1 is shown the plasmalogen content in the normal brain as a function i
n moles stearyl a~ohol
T N []
N ~r
1o{
| ]L
Qk
Qk
l
]p
I i
Jp
]
i
mg proteins
total activity ~er brain in vitro
Fig. '2. Stearyl-alcohol biosynthesis iv normal and dysrnyelinating mutants (Quaking and J~mpy). N, normal; Qk, Quaking; Jp, Jimpy.
229
of age. The highest speed of deposition is around 15 days of age (between 12 and 20 days); very young animals (3-day-old) contain 18% of the adult !eve]. In the adult the values are 14.9 -+ 0.9 pmole/g vrain, or 6.1 _+ 0.6.pmo]e/br~no in Quaking these values are, respectively, 9.1 + 0.8 and 3.6 -+ 0.5. This curve is similar to the one obtained in the rat [16]. Steary]-alcohol biosynthesis is maximal at 15 days and slowlydecreases thereafter. This unexpected light decrease is probably due to the occurrence of plasmalogens beside myelin and to a greater turn-over of plasmalogens than other myelin ]ipids. In Fig. 2 is shown stearyl-alcohol biosynthesis in 18
This work was supported by I.N.S.E.R.M. (C.L. No 75.1. 196.6). The authors ~re grateful to Professor Ailhaud for judicious advice during acyi-CoA synthesis wad to F. Lachapeile and A. De Almeida for breeding the anima]s. REFERENCES 1. Baumaun, N.A., Jacque, C., Pollet, S. and H~pin, M.L., Fatty acid and lipid composition of the brmn of a myelin deficient mutant, the Quaking mouse, Europ..J. Biochem., 4 (1968) 3 4 ~ 3 4 4 , 2 Bell,O'Ei, Blank, M.L. and Snyder, F., The incorporation of ~ O and ~4C from long chain alcohols into the ~dkyl and alk-l-enylethers of phospholipids of developing brain, Biochim! biophys. Acta (Amst,), 231 (1970) 577--593. 3 Bourre, JIM,, Poller,S.A., Dubois, G. et Baumann, N.A., Biosynthdse des acides gras trds longues cha~hes dans les micrOsomes de cerveau de souris,C.R. Acad. Sci. (Paris), 271 (1970) 1221--1223. 4 Bourre~ J.i~I.,Po|let,S.A., Daudu, O.L. and Baumanr~, N.A., Evoh~tion in mouse brmn microsomes of lipidsand their constituents during myelination, Brain Res., 51 (1973) 225--239i 5 Bour~ Daudu, O~L, and B~umann~ N.A., Lignocericacid in the developing brain. Activities of mitochondri~ ace~l-CoA dependent synthesis and microsom~ ma]onyl system in relation to myelination, Europ: J. Biochem°, 72 (!977) .
4i~,47i
.
.
.
230
6 Bourre, J.M,, C~ss~ne: C., Larrouquere-Re~nier, S. and Daffier, D., Occurrence of ~dkane in brain myelin. Co mpariron between normal and Quaking mouse, J. N~urochem., 29 (1977) 645--648. 7 Dorzr~an,R.V., Freysz, L. and Morrocks, L.A., Synthesis of ethanolamine phosphoglycerides by microsomes from the brains of Jimpy and Quaking mice, J. Neurochem., 29 (197~') 231--233. 8 Goldman, P. and Vagelos, R., Chemic~ synthesis or acyl C o A esters,J. biol. Chem., 236 (1961) 2620--2629. 9 Gottfried,E.L. and Rapport~ Id.M., The biochemistry of plasmalogens, J. biol. chem., 237 (1962) 329--333. 10 Hajra,A.K. Biosynthesis of alk~.'l~thercontaining lipid from dihydro~yacetc~ne phosphate, Biochem. Biophys. Res. Commun., 164 (1969) 486-492. 11 Natraj~r~Y. and S~try, P.S.,Conversion of (1-14C)palmiticacid to (1-14C)hexadecanol by developing rat brain cellfree preparation, J. Neurochem., 26 (I '976) 107--113. 12 Paturneau~Jou~s, M.~ Baumann, N. and Bourre, J.M., Elongatioy, of p~Imityl-CoA in mouse brain mitochondria. Comparison with stearyl-CoA, Bioc~em. Biophys. Res. Commun., 4 (1976) 1326--1334. 13 Schmid, H.H. and Tak~ashi, T., Reductive and oxidative bio~'ntbesis of plasmalogens in myelinating brain J. biol.Chem., 11 (1970) 412--419. 14 Stoff~|~'W. and Lekim, D., On the stereospecificityof the bJJchemical dehydrogenation of the 1-O-alkylglyceryl to the 1-O-alk-l'-enylglyceryl ether bond, Hoppe-Seyler~s Z. Physiol. Chem., 352 (1971) 501--511. 15 Takahashi, T. and Schmid, T., Long chain alcohorin mammalian tissue,Chem. Phys. Lipids, ~ (1970) 243--246. 16 Wells,M.A. and Dittmer, J.C., A comprehensive study of the postnatal changes in the concentration of the lipidsof developing rat brain,biochemistry, 6 (1967) 3169--3175.