Substrate specificity -

Enzymes have the characteristic of acting only on specific substances (substrates) and causing specific chemical reactions. This is called the enzyme's substrate specificity. In the past, the relationship between enzymes and substrates was likened to a key and a keyhole. This concept is correct, but with the advances being made in enzyme chemistry today, it has become clear that enzymes are not as rigid as a key, and that they undergo changes in their higher-order structure when binding to a substrate, and that the site that determines substrate specificity is composed of specific amino acid residues. For many enzymes, the three-dimensional structure of the enzyme-substrate complex has also been determined, and it is becoming possible to explain the reaction mechanism at the molecular level.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

酵素は特定の物質(基質)にのみ作用し，特定の化学反応を起こさせる特徴を有する．これを酵素の基質特異性という．かつては酵素と基質の関係を鍵と鍵穴にたとえた．この概念は正しいが，酵素化学の進歩した現在では，酵素は鍵のように堅いものではなく，基質との結合に際し，高次構造の変化を起こすこと，あるいは基質特異性を決定する部位が特定のアミノ酸残基によって構成されていること，などが明らかになっている．多くの酵素では，酵素-基質複合体の立体構造も決定され，反応機構を分子レベルで説明できるようになりつつある．

出典　森北出版「化学辞典（第2版）」化学辞典 第2版について　情報