解説24．高分子合成・反応における最近の進歩
(10) 酵素重合における最近の進歩
2022 年 59 巻 3 号 p. 89-95
詳細
2022 年 59 巻 3 号 p. 89-95
Enzymatic polymerization catalyzed by various types of enzymes is a green synthetic technique to synthesize polymers with great advantages against conventional chemical synthesis. Proteases, which generally catalyze hydrolytic cleavage of proteins and polypeptides, have been utilized for enzymatic polymerization to synthesize various types of polypeptides from amino acid ester monomers. Kinetic control in the activation of carboxylate moiety of amino acid monomers at the catalytic center in proteases enables consecutive aminolysis over hydrolysis, leading to polypeptide formation. Because protease-catalyzed polymerization of amino acid esters proceeds in a regio- and stereoselective manner regulated by substrate specificity, α-linked polypeptides are selectively synthesized without protecting a reactive side group of amino acid monomers. Polymerizing dipeptide or tripeptide ester monomers results in the formation of polypeptides possessing periodic sequences. Rational combination of oligopeptide sequences and a suitable protease provides polypeptide materials featured by periodic introduction of specific functional residues. Unnatural amino acids are unable to polymerize via protease-catalyzed polymerization due to the poor recognition in substrate pockets of proteases. Flanking unnatural amino acid with natural （proteinogenic） ones in oligopeptide monomers mitigates the mismatch of substrate specificity, leading to periodic introduction of unnatural amino acid residues in polypeptides.
