Departamento de Biocatálisis, ICP-CSIC, Marie Curie 2, Campus UAM-CSIC Cantoblanco, 28049 Madrid, Spain; Student of Departamento de Biología Molecular, Universidad Autónoma de Madrid, Darwin 2, Campus UAM-CSIC, Cantoblanco, 28049 Madrid, Spain.
Faculty of Nutrition, Alfenas Federal Univ., 700 Gabriel Monteiro da Silva St, Alfenas, MG 37130-000, Brazil.
Int J Biol Macromol. 2022 Jun 15;210:682-702. doi: 10.1016/j.ijbiomac.2022.04.224. Epub 2022 May 1.
Pepsin is a protease used in many different applications, and in many instances, it is utilized in an immobilized form to prevent contamination of the reaction product. This enzyme has two peculiarities that make its immobilization complex. The first one is related to the poor presence of primary amino groups on its surface (just one Lys and the terminal amino group). The second one is its poor stability at alkaline pH values. Both features make the immobilization of this enzyme to be considered a complicated goal, as most of the immobilization protocols utilize primary amino groups for immobilization. This review presents some of the attempts to get immobilized pepsin biocatalyst and their applications. The high density of anionic groups (Asp and Glu) make the anion exchange of the enzyme simpler, but this makes many of the strategies utilized to immobilize the enzyme (e.g., amino-glutaraldehyde supports) more related to a mixed ion exchange/hydrophobic adsorption than to real covalent immobilization. Finally, we propose some possibilities that can permit not only the covalent immobilization of this enzyme, but also their stabilization via multipoint covalent attachment.
胃蛋白酶是一种在许多不同应用中使用的蛋白酶，在许多情况下，它以固定化形式使用，以防止反应产物受到污染。这种酶有两个特点，使其固定化变得复杂。第一个特点与它表面上初级氨基基团的缺乏有关（只有一个赖氨酸和末端氨基基团）。第二个特点是它在碱性 pH 值下的稳定性差。这两个特点使得这种酶的固定化被认为是一个复杂的目标，因为大多数固定化方案都利用初级氨基基团进行固定化。本文综述了一些获得固定化胃蛋白酶生物催化剂及其应用的尝试。阴离子基团（天冬氨酸和谷氨酸）的高密度使酶的阴离子交换更简单，但这使得许多用于固定化酶的策略（例如，氨基戊二醛载体）更与混合离子交换/疏水吸附有关，而不是真正的共价固定化。最后，我们提出了一些可能性，不仅可以允许这种酶的共价固定化，还可以通过多点共价连接来稳定它们。
