Discovering chemistry
Discovering chemistry

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Discovering chemistry

2 Steric effects in enzymes

Enzymes are protein molecules that facilitate vital biological reactions.

They can do this because their molecular surfaces contain active sites to which the molecules participating in the reaction (known as substrates) can become temporarily bound.

The active sites are crevices in the enzyme surface, often of a complicated shape. The substrate has the precise shape required to fit the opening, and potential competitors that lack this shape are excluded (Figure 4). The need for the substrate to bind to the enzyme surface will often weaken other bonds within the substrate itself, encouraging the changes that the enzyme facilitates.

Described image
Figure 4 A model for enzyme action: only one of the three molecules has the shape required to fit the cavity on the enzyme surface; the other two are excluded
DC_1

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371