Cook H W
Lipids. 1979 Sep;14(9):763-7. doi: 10.1007/BF02533513.
Developing rat brain has the capacity for either delta 9 or delta 6 desaturation of fatty acids. In liver, evidence supports the existence of separate enzymes for each reaction, but it is not known whether in brain delta 9 or delta 6 desaturation of saturated fatty acids involves distinct enzymes. We have used fatty acids, including the cyclopropene fatty acid, sterculic acid, to alter desaturation activities with substrates that are desaturated predominantly in the delta 9 position or in the delta 6 position. In addition, differential alteration of desaturation of palmitic acid, a substrate that can be desaturated in either the delta 9 or delta 6 positions by brain preparations from neonatal rats, was examined. Sterculate reduced delta 9 desaturation of palmitate 80--90% but reduced delta 6 desaturation only 35%. In contrast, linoleic acid preferentially reduced delta 6 desaturation of palmitate. Thus, delta 9 desaturation of saturated fatty acids appears to be catalyzed by an enzyme or enzyme site distinct from that for delta 6 desaturation. Accordingly, these activities may be independently regulated during crucial stages of brain development.
发育中的大鼠大脑具有对脂肪酸进行Δ9或Δ6去饱和的能力。在肝脏中，有证据支持每种反应存在单独的酶，但尚不清楚在大脑中饱和脂肪酸的Δ9或Δ6去饱和是否涉及不同的酶。我们使用了包括环丙烯脂肪酸、苹婆酸在内的脂肪酸，来改变主要在Δ9位或Δ6位去饱和的底物的去饱和活性。此外，还研究了棕榈酸（一种可被新生大鼠脑匀浆在Δ9或Δ6位去饱和的底物）去饱和的差异变化。苹婆酸使棕榈酸的Δ9去饱和降低了80% - 90%，但仅使Δ6去饱和降低了35%。相反，亚油酸优先降低棕榈酸的Δ6去饱和。因此，饱和脂肪酸的Δ9去饱和似乎由一种与Δ6去饱和不同的酶或酶位点催化。相应地，在大脑发育的关键阶段，这些活性可能受到独立调节。
