Wang Yu, Tian Yu, Rennison Andrew Philip, Blennow Andreas, Westh Peter, Svensson Birte, Møller Marie Sofie
Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
JACS Au. 2025 Jan 14;5(1):55-60. doi: 10.1021/jacsau.4c00932. eCollection 2025 Jan 27.
Interfacial enzyme catalysis is widespread in both nature and industry. Granular starch is a sustainable and abundant raw material for which a rigorous correlation of the surface structure with enzymatic degradation is lacking. Here pullulanase-catalyzed debranching of 12 granular starches varying in amylopectin contents and branch chain contents and lengths is shown to present a biphasic relationship characteristic of the Sabatier principle. Introducing normalization of the specific rate ( / ) by a substrate-dependent constant , related to the Arrhenius prefactor of , reveals that optimal activity according to the Sabatier principle occurs at moderate substrate binding strength. The density of pullulanase attack sites (Γ), determined using combined conventional and inverse Michaelis-Menten kinetics, was increased by branching enzyme treatment. Medium Γ and branch chain length conferred the highest activity depending on substrate load. Correlation analysis demonstrated that starch granular crystallinity, surface order, and average branch chain length influence the enzymatic degradation by affecting the constant. Therefore, should be considered together with the enzyme binding strength to understand the degradation of starch granules. The Sabatier principle could serve as a diagnostic tool to characterize enzyme performance on substrates having different surface structures and guide rational modification of granular starches for specific purposes.
界面酶催化在自然界和工业中都广泛存在。颗粒淀粉是一种可持续且丰富的原材料，但目前缺乏其表面结构与酶促降解之间的严格关联。本文表明，支链淀粉酶催化的12种支链淀粉含量、支链含量及长度各异的颗粒淀粉的去分支反应呈现出萨巴蒂尔原理所特有的双相关系。通过与底物相关常数对特定速率（/）进行归一化处理，该常数与的阿累尼乌斯前因子相关，结果表明，根据萨巴蒂尔原理，最佳活性出现在中等底物结合强度时。使用传统和逆米氏动力学相结合的方法测定的支链淀粉酶攻击位点密度（Γ），通过分支酶处理而增加。中等的Γ和支链长度根据底物负载赋予了最高活性。相关性分析表明，淀粉颗粒结晶度、表面有序度和平均支链长度通过影响常数来影响酶促降解。因此，在理解淀粉颗粒的降解时，应将与酶结合强度一并考虑。萨巴蒂尔原理可作为一种诊断工具，用于表征酶在具有不同表面结构的底物上的性能，并指导为特定目的对颗粒淀粉进行合理改性。
