Hydrolytic enzymes are the enzymes that catalyse the hydrolysis of various bonds such as peptide, ester, glycosidic, ether, carbon-carbon bonds, carbon-halide bonds and P-N bonds.
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They utilise water to break the bonds. They break a larger molecule into smaller molecules.
Introduction
Enzymes are biocatalysts. They catalyse all biological reactions. All the enzymes are divided into six different classes. Hydrolytic enzymes are grouped under the class Hydrolases. They are a very important part of our body and take part in various biological processes.
Various enzymes such as lipases, proteases, carbohydrases, nucleotidases are responsible for breaking down lipids, proteins, carbohydrates, nucleic acids, respectively.
The basic reaction catalysed by a hydrolytic enzyme or hydrolases is:
A–B + H2O → A–OH + B–H
Nomenclature and Classification
Hydrolases are classified as EC 3. EC stands for “Enzyme Commission number”. It is a numerical system of classifying enzymes based on the reaction catalysed by them. The six classes of enzymes are:
- EC 1 – Oxidoreductases
- EC 2 – Transferases
- EC 3 – Hydrolases
- EC 4 – Lyases
- EC 5 – Isomerases
- EC 6 – Ligases
Hydrolases are further classified into various subclasses based on the bond they hydrolyse. E.g.
EC 3.1 – hydrolysing ester bonds, e.g. esterase, lipase, phosphodiesterase, nuclease, etc.
EC 3.2 – hydrolysing glycosidic bonds, e.g. glycoside hydrolase, amylase, maltase, etc.
EC 3.3 – hydrolysing ether bonds
EC 3.4 – hydrolysing peptide bonds, e.g. Proteases, peptidases, pepsin, trypsin, chymotrypsin, etc.
EC 3.5 – hydrolysing carbon-nitrogen bonds, other than peptide bonds, e.g. urease, etc.
EC 3.6 – hydrolysing acid anhydrides, e.g. helicases, GTPase, etc.
EC 3.7 – hydrolysing carbon-carbon bonds
Hydrolases are named with the substrates name used as a prefix, i.e. “substrate hydrolase”. They are commonly named “substrate-ase” e.g. nuclease, protease, etc.
Examples of Hydrolytic Enzymes
Find below the names of some of the most common hydrolytic enzymes and the reactions catalysed by them:
- Lipase – It catalyses the hydrolysis of fats. It is an example of esterases. E.g. pancreatic lipase, lysosomal lipase. Pancreatic lipase converts triglycerides to monoglycerides and two fatty acids. Lysosomal lipase digests lipids and cholesterol to free fatty acids.
- Amylase – Amylase is a type of glycoside hydrolases. It catalyses the hydrolysis of starch into sugars, trisaccharides, disaccharides, etc. E.g. salivary amylase, pancreatic amylase. Salivary amylase converts starch to maltose. Pancreatic amylase converts starch to disaccharides.
- Protease – It catalyses the breakdown of proteins into smaller peptides, single amino acids. E.g. pepsin, trypsin, chymotrypsin, elastase, etc. Pepsin is secreted as pepsinogen by gastric glands, it converts proteins to peptones and proteoses. Trypsin and chymotrypsin are secreted by pancreas as zympgen, they act on partially hydrolysed proteins and convert it to dipeptides.
- Phosphatase – It catalyses the removal of phosphate moiety from the substrate, e.g. nucleotidase, it catalyses the hydrolysis of nucleotides to form nucleosides. Other examples are glucose-6-phosphatase, fructose-1,6-bisphosphatase, etc. involved in gluconeogenesis.
This was all about the Hydrolytic Enzymes. Learn more about other related concepts for NEET, only at BYJU’S.
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