Enzyme vs Protein
Proteins and enzymes are biological macromolecules, made up of many amino acids linked together as linear chains. Amino acid is the basic structural and functional unit of these macromolecules. An amino acid molecule is composed of four basic groups; namely, amino group, side chain (R- group), carboxyl group, and hydrogen atom, which are bonded to a central carbon atom. Basically there are twenty naturally occurring amino acids, and they differ only by the side chain (R-group). The order of amino acids determines the structure and functions of protein and enzymes.
Enzymes are the special three-dimensional globular proteins that can act as biological molecules, to catalyze and regulate chemical reactions in organisms. In a single cell, there are thousands of different enzymes. That is because almost every reaction in a cell requires its own specific enzyme. Normally enzymes cause cellular reactions to occur million times faster than corresponding uncatalyzed reactions. The active sites present on the surface of enzyme determine their degree of specificity. Types of enzyme specificity include absolute specificity, stereochemical specificity, group specificity, and linkage specificity. Active sites are the cracks or hollows on an enzyme surface caused by the formation of tertiary structure. Some active sites bind only one particular compound, while others can bind group of closely related compounds. Enzymes are unaffected by the reaction that they catalyze. There are four factors affect the activity of enzyme, namely; temperature, pH, substrate concentration, and enzyme concentration.
Proteins are the most diverse biological macromolecules, both functionally and structurally. They are polymers of amino acids. The sequence of amino acid determines their basic structure and function. The basic functions of proteins are enzyme catalysis, defense, transport, support, motion, regulation, and storage. The structure of proteins can be expressed in terms of a hierarchy of four levels; primary, secondary, tertiary, and quaternary. Amino acid sequence is the protein’s primary structure. Secondary structure formation is due to the regular interaction of groups in the peptide backbone with the formation of hydrogen bonds. This produces two different kinds of structures, namely; beta (β) – pleated sheets, and alpha (α) – helices or coils. Fold and links of a protein molecule finally make its 3-D shape called tertiary structure. Proteins with multiple polypeptides result quaternary structure.
What is the difference between Enzyme and Protein?
• All the enzymes are globular proteins, but not all proteins are globular. Some proteins are globular while some are not (Fibrous portions have long thin structures).
• Unlike other proteins, enzymes can act as catalysts, to catalyze and regulate biological reactions.
• Enzymes are functional proteins, whereas proteins can be either functional or structural.
• Unlike other proteins, enzymes are highly substrate specific molecules.
• Proteins can be digested or broken down by enzymes (proteases).