权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Kinetic study on enzymatic degradation of biodegradable polyesters

生物降解聚酯酶促降解动力学研究

基本信息

批准号：
16550139
负责人：
YAMASHITA Koichi
金额：
$ 2.3万
依托单位：
RIKEN
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16550139/
关键词：
biodegradable polyester enzymatic degradation adsorption QCM esterase AFM

项目摘要

Enzymatic degradation of biopolyesters was investigated by a quartz crystal microbalance (QCM) and an atomic force microscope (AFM). In the case of enzymatic degradation of a melt-crystallized film of poly[(R)-3-hydroxybutyrate] (P(3HB)) by PHB depolymerase from Ralstonia pickettii T1, the erosion rate was not constant during the degradation due to heterogeneity of the film composed of an amorphous region and a crystalline region. Characteristic profiles were also observed for dependence of the erosion rate on depolymerase concentrations. The rate increased with enzyme concentrations to reach a maximum value at 1.0 μg/mL, and then decreased at higher enzyme concentrations. This dependence can be explained in terms of mutual steric hindrance among adsorbed enzyme molecules. The characteristic dynamic adsorption behavior of PHB depolymerase was also revealed. In contrast to the melt-crystallized P(3HB) film, the erosion rate of an amorphous poly [L-lactide] (PLLA) film by proteinase K was constant during degradation, indicating that the PLLA film is homogeneously amorphous. The erosion rate increased with enzyme concentration and remained constant under the conditions of [proteinase K] > 100 μg/mL. The erosion rate was proportional to the adsorbed amount of the enzymes. Adsorption of proteinase K was irreversible despite lack of the substrate-binding domain, so that the enzyme molecules on the film could be directly observed by AFM. Transformation of the molecules caused by packing in high density on the surface was observed at higher enzyme concentrations. The "footprint" of the individual proteinase K molecule on the PLLA film after enzymatic degradation suggests that the enzyme moves on the surface to hydrolyze the film around its. The differences between proteinase K and the PHB depolymerase might result from whether these enzymes possess the substrate-binding domain or not.

利用石英晶体微天平（QCM）和原子力显微镜（AFM）研究了生物聚酯的酶降解过程。在聚[（R）-3-羟基丁酸酯]（P（3 HB））的熔融结晶膜通过来自皮氏罗尔斯通氏菌T1的PHB解聚酶的酶促降解的情况下，由于由无定形区域和结晶区域组成的膜的不均匀性，在降解期间侵蚀速率不是恒定的。还观察到侵蚀速率对解聚酶浓度的依赖性的特征曲线。随着酶浓度的增加，酶解速率增加，在1.0 μg/mL时达到最大值，在较高的酶浓度下，酶解速率下降。这种依赖性可以解释在吸附的酶分子之间的相互空间位阻。揭示了该树脂对PHB解聚酶的动态吸附特性。与熔融结晶的P（3 HB）膜相比，蛋白酶K对无定形聚[L-丙交酯]（PLLA）膜的侵蚀速率在降解过程中是恒定的，表明PLLA膜是均匀无定形的。在[蛋白酶K] > 100 μg/mL的条件下，腐蚀速率基本不变。酶的侵蚀速率与酶的吸附量成正比。由于蛋白酶K的吸附是不可逆的，尽管没有底物结合结构域，因此AFM可以直接观察到膜上的酶分子。在较高的酶浓度下，观察到由表面上的高密度堆积引起的分子转化。酶降解后PLLA膜上单个蛋白酶K分子的“足迹”表明酶在表面上移动以水解其周围的膜。蛋白酶K和PHB解聚酶之间的差异可能是由于这些酶是否具有底物结合结构域。

项目成果

期刊论文数量（26）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Autoregulator Protein PhaR for Biosynthesis of Polyhydroxybutyrate [P(3HB)] Has Possible Two Separate Domains That Binds to the Target DNA and P(3HB) :

用于聚羟基丁酸酯 [P(3HB)] 生物合成的自动调节蛋白 PhaR 可能具有两个单独的结构域，可与靶标 DNA 和 P(3HB) 结合：

DOI：
发表时间：
2007
期刊：
J. Bacteriology
影响因子：
0
作者：
Yasuhiro;Kajihara;Akiko;Yoshihara;Kiriko;Hirano;Naoki Yamamoto;Miwa Yamada;Miwa Yamada
通讯作者：
Miwa Yamada

Surface properties and enzymatic degradation of end-capped poly(l-lactide)

DOI：
10.1016/j.polymdegradstab.2005.08.015
发表时间：
2006-06
期刊：
Polymer Degradation and Stability
影响因子：
5.9
作者：
K. Kurokawa;K. Yamashita;Y. Doi;H. Abe
通讯作者：
K. Kurokawa;K. Yamashita;Y. Doi;H. Abe

Surface Properties and Enzymatic Degradation of End-capped Poly(1-lactide)

封端聚(1-丙交酯)的表面性质和酶降解

DOI：
发表时间：
2006
期刊：
Polymer Degradation and Stability 91・6
影响因子：
0
作者：
Yasuhiro;Kajihara;Akiko;Yoshihara;Kiriko;Hirano;Naoki Yamamoto;Miwa Yamada;Miwa Yamada;Kenji Kurokawa
通讯作者：
Kenji Kurokawa

Functional Mapping of Amino Acid Residues Responsible for DNA Binding

负责 DNA 结合的氨基酸残基的功能图谱