Why do enzymes denature at high temperatures?

Question

it would be good if anyone could give a detailed scientific explanation please!

Answer 1

Enzymes are proteins, meaning that they are strings of amino acids connected together by peptide bonds that form a certain structure. Proteins have several different structures in how they may exist - primary, secondary, tertiary, and quaternary. The primary structure of a protein is just the linear sequence of amino acids. The secondary structure involves hydrogen bonding between amino acids. The tertiary structure involves bonding between R-groups and the quaternary structure usually involves multiple protein interactions.

Denaturing at high temperatures occurs because high temperatures rupture some of the bonding that occurs in these quaternary/tertiary/and secondary protein structures. Once these bonds are broken, the enzyme (protein) is reduced to its primary structure with just peptide bonds occurring - the functional structure of the enzyme is lost and it is no longer functional. This works for most proteins. In the case of the enzyme, however, when the structure is lost, the active site and allosteric site also lose their functionality and therefore no substrate may bind to the enzyme.

Answer 2

Denatured Enzymes

Answer 3

Like all proteins, enzymes are made as long, linear chains of amino acids that fold to produce a three-dimensional product. Each unique amino acid sequence produces a unique structure, which has unique properties. Individual protein chains may sometimes group together to form a protein complex. Most enzymes can be denatured—that is, unfolded and inactivated—by heating, which destroys the three-dimensional structure of the protein. Depending on the enzyme, denaturation may be reversible or irreversible.

Answer 4

Proteins consist of folded chains of amino acids. The way the amino acid chain folds up creates areas where the protein can interact with other molecules, normally a cleft where bondable parts of the protein are exposed; this is the active site. Other molecules (substrates) interact with the enzyme's active site, and these are normally quite specific- for the reaction to work, the substrates have to be the right shape to fit in the active site.

The chain is kept in the right shape by lots of hydrogen bonds. To separate bonds, a certain amount of energy is required (activation energy). This can be supplied in several ways, one of the most common being heat energy.

When enzymes are heated, the hydrogen bonds keeping the chain folded up separate and the enzyme changes its shape. Once the active site has changed shape, the enzyme cant interact properly with the substrates, and stops working.

This is known as denaturation- where the enzyme looses its natural shape

Answer 5

Enzymes are made largely, if not all, of protein. Proteins are made of amino acids and amino acids have functional groups that allow for folding due to electrostatic and ionic attractions.

When placed under high heat (or change in pH or salt), the attractions such as ionic bonds and hydrogen bonds (that keep a protein folded in a particular conformation) are disrupted, leading to denaturation.

You have seen this when cooking the white of an egg....starts off running and clear, but becomes white and opaque after heating.

Answer 6

Enzymes are proteins and undergo essentially irreversible denaturation (i.e.. conformational alteration entailing a loss of biological activity) at temperatures above those to which they are ordinarily exposed in their natural environment. Hope that helps.

Answer 7

enzymes are made of protein. protein denatures as temp increases - think of a steak (protein)...what happens when you cook it?

Answer 8

because theyre made up of proteins, and proteins denature after reaching a certain temperature.