effects that enzymes can have on substrates

Even small changes in the reactant molecule can stop the enzyme from catalysing its reaction. Īn important point about enzymes is that they are very specific about what they can catalyse. If you look very carefully, you might also spot two pink, non-protein structures hidden in the main structure. If you can't, you obviously didn't read the page about protein structure mentioned above! You should be able to identify the alpha-helices and beta-pleated sheets. Note: This diagram was obtained from the RCSB Protein Data Bank. This is a model of catalase, showing the globular structure - a bit like a tangled mass of string: One molecule of catalase can decompose almost a hundred thousand molecules of hydrogen peroxide every second. The enzyme catalase will also do this - but at a spectacular rate compared with inorganic catalysts. You are probably familiar with the use of catalysts like manganese(IV) oxide in decomposing hydrogen peroxide to give oxygen and water. These globular proteins can be amazingly active catalysts. We aren't interested in those in this topic. The other type of proteins (fibrous proteins) have long thin structures and are found in tissues like muscle and hair. Unless your syllabus specifically asks for a particular enzyme, there is no need for you to remember the details.Įnzymes are mainly globular proteins - protein molecules where the tertiary structure has given the molecule a generally rounded, ball shape (although perhaps a very squashed ball in some cases). Important: The specific examples of the enzymes that you will find on this page are only intended to give you a feel for the way that enzymes work. Read the protein structure page first and come back here later. If you don't have a reasonable knowledge of the structure of proteins and the sorts of attractions that can be found in them, you may not understand bits of the present page.

Note: This page follows on from a page about protein structure.

If you want detailed knowledge about enzymes for a biology or biochemistry course, you are probably in the wrong place! This is just an introduction. You should realise that this is written to cover the needs of a number of UK-based chemistry syllabuses for 16 - 18 year olds. This page is an introduction to how proteins can work as enzymes - biological catalysts.

Effects that enzymes can have on substrates