Enzymes: Catalysts of Life | 酶：生命的催化剂

📚 Enzymes: Catalysts of Life | 酶：生命的催化剂

You take a breath, digest a meal, and blink your eyes. Every one of these actions depends on thousands of enzyme-controlled reactions. For Edexcel IGCSE Biology, enzymes are one of the most examined topics, so a clear understanding of how they work is essential.

你吸一口气、消化一顿饭、眨一下眼睛，每一项动作都依赖着成千上万场由酶控制的化学反应。在 Edexcel IGCSE 生物学科中，酶是最常考的内容之一，因此透彻理解酶的工作原理至关重要。

1. What Are Enzymes? | 什么是酶？

An enzyme is a biological catalyst. A catalyst is a substance that speeds up a chemical reaction while remaining unchanged at the end. Most enzymes are globular proteins made from long chains of amino acids folded into a unique three-dimensional shape.

酶是一种生物催化剂。催化剂是指能加快化学反应而自身在反应结束后不发生变化的物质。绝大多数酶是球状蛋白质，由氨基酸长链折叠成独特的三维结构。

One particularly important region of the enzyme is called the active site. This is the part of the enzyme where the reacting molecule, known as the substrate, binds. The shape of the active site is exactly complementary to the shape of the substrate.

酶上一个特别重要的区域叫做活性位点。这是酶与反应物分子（称为底物）结合的部位。活性位点的形状与底物的形状恰好互补。

Enzyme names usually end with ‘-ase’, such as amylase, protease and catalase. Amylase breaks down starch, protease breaks down proteins, and catalase breaks down hydrogen peroxide.

酶的名称通常以 ‘-ase’ 结尾，如淀粉酶 amylase、蛋白酶 protease

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