# Explain why denaturation of an enzyme results in loss of its catalytic activity.

> IB DP Biology Higher Level (2023 syllabus) — B1.2 Proteins · Explain · 4 marks

## Mark scheme (4 marks)

1. Denaturation disrupts non-covalent interactions (hydrogen bonds, ionic bonds, hydrophobic interactions) that maintain tertiary structure
2. The three-dimensional (tertiary) structure / conformation of the enzyme is altered / unfolded
3. The active site changes shape so substrate can no longer bind (induced fit / complementary shape is lost)
4. Without substrate binding, the enzyme–substrate complex cannot form and so catalysis / lowering of activation energy does not occur

## Key terms

- [denaturation](https://www.gradenine.co.uk/glossary/denaturation)

## Related

- [Revision notes for IB DP Biology Higher Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-denaturation-of-an-enzyme-4bb4a8b7) · Published by Druglandscape Ltd.