Synthesis and physicochemical properties of protein conjugates with water-soluble poly(alkylene oxides).
Synthesis and physicochemical properties of protein conjugates with water-soluble poly(alkylene oxides).
复制标题
水溶性聚环氧烷蛋白缀合物的合成和理化性质。
DOI：
10.1021/bc00034a007
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发表时间：
1995
影响因子：
4.7
通讯作者：
N. N. Magretova
中科院分区：
文献类型：
--
作者：
I. N. Topchieva;N. V. Efremova;N. Khvorov;N. N. Magretova
以一醛类聚合物衍生物为氨基修饰剂，合成了蛋白质(牛血清白蛋白(BSA)和α-糜蛋白酶(CHT))与聚乙二醇的偶联物以及环氧乙烷和环氧丙烷的两亲性嵌段共聚物(丙烷醇)。得到了四种不同类型的偶联物，它们的疏水嵌段位置和聚合物链分布类型不同。建立了与丙黄醇偶联的蛋白质的纯化和鉴定方法。结果表明，基于CHT的偶联物对所研究的两种底物--N-苯甲酰-L-酪氨酸和酪蛋白--都保持了很高的酶活性，直到高度修饰(每个蛋白质分子11个聚合链)。同时，CHT-丙醇偶联物具有较高的热稳定性，其稳定效果随改性程度的增加而增加。结果表明，变性对蛋白质沉降系数的影响可以忽略不计。根据疏水层析法、沉降法和差示扫描量热法得到的数据，提出了蛋白质-丙酚结合物的构象模型。据推测，在水溶液中，共轭化合物形成致密的结构，类似于分子内胶束，由聚环氧丙烷基团之间的疏水相互作用稳定。
Conjugates of proteins (bovine serum albumin (BSA) and alpha-chymotrypsin (CHT) with poly(ethylene glycol) and amphiphilic block copolymers of ethylene oxide and propylene oxide (proxanols) were synthesized, using monoaldehyde polymer derivatives as the amino group modifying reagents. Four types of conjugates varying in the placement of hydrophobic block and type of polymer chain distribution were obtained. Methods of purification and characterization of proteins conjugated with proxanols were developed. It was shown that conjugates based on CHT retain high enzymatic activity toward both substrates investigated--N-benzoyl-L-tyrosine and casein-up to high degrees of modification (11 polymer chains per protein molecule). At the same time, CHT--proxanol conjugates were characterized by higher thermostability, the stabilizing effect increasing in parallel with the degree of modification. It was shown that the alteration of sedimentation coefficients of proteins caused by modification was negligible. On the basis of data obtained by the methods of hydrophobic chromatography, sedimentation, and differential scanning calorimetry, conformational models of protein-proxanol conjugates were suggested. It was supposed that conjugates form compact structures in aqueous solutions, which resemble intramolecular micelles, stabilized by hydrophobic interactions between poly(propylene oxide) blocks of proxanols.