Amino Acids and Their Polymers

Which functional groups are always involved in amide bonds between amino acids?

The amide bonds between amino acids always involve the central amino and central carboxyl groups. The side chains are not involved in the bonding.

In 1926, the American chemist James B. Sumner reported the first isolation and crystallization of an enzyme.

The enzyme he isolated was urease, which hydrolyzes urea, a constituent of urine, into ammonia and carbon dioxide.

peptide

an organic compound formed by a combination of amino acids in which the amino group of one acid is united with the carboxyl group of another through an amide bond

amino acid

an organic compound having amino (—NH2) and carboxyl (—COOH) groups in the same molecule; proteins are made from the 20 naturally occurring amino acids

protein

any peptide with more than 100 amino acids

What is the process by which amino acids are added to peptides to form long chains?

condensation polymerization

peptide bond

the bond between the carbonyl group of one amino acid and the nitrogen of the next amino acid in the peptide chain

Coenzymes

Coenzymes are metal ions or small organic molecules that must be present for an enzyme-catalyzed reaction to occur. Many water-soluble vitamins, such as B vitamins, are coenzymes. Metal ions that act as coenzymes include the cations of magnesium, potassium, iron, and zinc. The enzyme catalase includes an iron(III) ion in its structure. Catalase catalyzes the breakdown of hydrogen peroxide to water and oxygen. 2H₂O₂(aq)→2H₂O(l) + O₂(g)

What determines the differences in the chemical and physiological properties of peptides and proteins?

Differences in the chemical and physiological properties of peptides and proteins result from differences in the amino acid sequence.

How do enzymes affect the rates of reactions in living things?

Enzymes increase the rates of chemical reactions in living things.

What is the general structure of an amino acid?

Amino acids have a skeleton that consists of a carboxyl group and an amino group, both of which are covalently bonded to a central carbon atom. The remaining two groups on the central carbon atom are hydrogen and an R group that -constitutes the amino acid side chain.

active site

a groove or pocket in an enzyme molecule into which the substrate (reactant molecule) fits; where the substrate is converted to products

substrates

a molecule on which an enzyme acts

enzymes

a protein that acts as a biological catalyst