Proteins, nucleic acids and polysaccharides are biomacromolecules. Lipids are small in molecular weight but appear in the acid-insoluble fraction because they are associated with membranes.
Macromolecules are large biomolecules of high molecular weight, usually found in the acid-insoluble fraction of living tissues.
After primary and secondary structure formation, the long protein chain folds into a compact three-dimensional form. This structure creates active sites or functional regions and is essential for biological activity of proteins.
Tertiary structure is the three-dimensional folding of a polypeptide chain upon itself.
Glycerol is trihydroxy propane. Each hydroxyl group can form an ester bond with the carboxyl group of a fatty acid. The resulting triester is a triglyceride, also called a fat or oil depending on melting point.
A triglyceride is formed when three fatty acid molecules are esterified with one glycerol molecule.
Alanine is an alpha-amino acid. Its alpha carbon is attached to –NH2, –COOH, H and a methyl side chain, –CH3.
Alanine has the structure CH3-CH(NH2)-COOH.
Enzymes possess active sites that bind specific substrates and form enzyme-substrate complexes. They greatly increase reaction rates without being consumed. They lower activation energy, show substrate specificity, work within narrow pH and temperature ranges, and can be inhibited by specific chemicals such as competitive inhibitors. Many require cofactors such as prosthetic groups, coenzymes or metal ions. Some catalytic nucleic acids are called ribozymes.
Enzymes are mostly proteins that act as highly specific biological catalysts, lower activation energy and work best at optimum temperature and pH.