Phase behavior of galactocerebrosides from bovine brain.
Phase behavior of galactocerebrosides from bovine brain.
复制标题
牛脑半乳糖脑苷脂的相行为。
DOI：
10.1021/bi00344a046
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发表时间：
1985
期刊：
影响因子：
2.9
通讯作者：
Jungalwala,FB
中科院分区：
文献类型：
--
作者：
Curatolo,W;Jungalwala,FB
用高效液相色谱法将牛脑苷脂（BOV-CER）分离成具有单一酰基链类型或具有相对均匀酰基链分布的牛脑苷脂组分。用差示扫描量热法研究了这些分离的皂苷级分的热行为。具有饱和酰基链（C16：0，C18：0，C24：0）的非羟基（n-酰基）脂肪酸糖苷（NFA-CER）的主要有序-无序转变温度TM为83 ℃，与链长无关。具有主要不饱和酰基链（C24：1）的NFA-CER在70 ℃显示TM。具有饱和羟基酰基链（C18：0 h，C24：0 h）的2-羟基脂肪酸糖苷（HFA-CER）在70-72 ℃显示TM。因此，天然存在的糖苷显示出高TM，其不显著依赖于酰基链长度，并且仅在很小程度上依赖于不饱和度和酰胺连接链中2-羟基分支的存在。分离的NFA-CER各自表现出先前针对未分级分离的NFA-CER描述的类型的亚稳态多态性[Curatolo，W.（1982）Biochemistry 21，1761]。HFA-CER中的多态性是复杂的，对于所研究的每个分离的酰基链级分观察到不同类型的热行为。在低温下长期储存时，未分级的HFA-CER和未分级的BOV-CER达到高度有序的凝胶状态，类似于NFA-CER容易达到的凝胶状态。这些结果表明，所有的糖苷都表现出亚稳态多晶型。然而，HFA-CER和BOV-CER达到稳定凝胶状态的动力学障碍大于NFA-CER。
Bovine brain cerebrosides (BOV-CER) were separated by high-performance liquid chroma-tography into cerebroside fractions with a single acyl chain type or with a relatively homogeneous acyl chain distribution. The thermal behavior of these isolated cerebroside fractions was studied by differential scanning calorimetry. Nonhydroxy (n-acyl) fatty acidcerebrosides (NFA-CER) possessing a saturated acyl chain (C16: 0, C18: 0, C24: 0) exhibit their major order-disorder transition temperature TM at 83 C, independent of chain length. NFA-CER possessing primarily unsaturated acyl chains (C24: l) exhibits TM at 70 C.2-Hydroxy fatty acid cerebrosides (HFA-CER), which possess a saturated hydroxyacyl chain (C18: 0h, C24: 0h), exhibit TM at 70-72 C. Thus, naturally occurring cerebrosides exhibit high TM's that do not depend significantly on acyl chain length and that depend only to a small degree on unsaturation and the presence of a 2-hydroxy branch in the amide-linked chain. Isolated NFA-CER’s each exhibit metastable polymorphism of the type previously described for unfractionated NFA-CER [Curatolo, W.(1982) Biochemistry 21, 1761]. Polymorphism in HFA-CER is complex, with a different type of thermal behavior observed for each isolated acyl chain fraction studied. On prolonged storage at low temperature, unfractionated HFA-CER and unfractionated BOV-CER reach a highly ordered gel state similar to that which is readily reached by NFA-CER’s. These results indicate that all cerebrosides exhibit metastable poly-morphism. However, the kinetic barriers to reaching the stable gel state are greater for HFA-CER and BOV-CER than for NFA-CER.