在化学实验室里大家熟知催化剂可以加速化学反应的进行。人体内食物的消化速度远比体外用强酸强碱水解为快。这是因为消化液中含有具催化作用的消化酶类。现已知体内几乎所有的生化反应都在不同的酶催化作用下进行。酶是活细胞的成分,由活细胞产生,但它们能在细胞内或细胞外同样起催化作用。故称为生物催化剂。一种酶只作用于一类化合物,或作用于一定的化学键,以促进一定的化学变化,得到一定的产物,这种现象称为酶的特异性。 It is well known in chemical laboratories that catalysts can speed up chemical reactions. The digestion of food in the body is far faster than strong acid-base hydrolysis in vitro. This is because the digestive juice contains catalytic digestive enzymes. It is now known that almost all biochemical reactions in the body are performed under different enzymatic catalysis. Enzymes are components of living cells that are produced by living cells, but they also act as catalysts either intracellularly or extracellularly. It is called biological catalyst. An enzyme acts only on a class of compounds, or act on a certain chemical bond to promote a certain chemical changes, to get a certain product, a phenomenon called enzyme specificity.