Differences between Intracellular and Extracellular Enzymes


Enzymes are soluble protein particles. They act as biocatalysts by increasing the pace of biochemical responses. Moreover, they do not alter the result of the reaction. They aid in digestion and many other biological processes. An enzyme can be either intracellular or extracellular. Sometimes, they can be both.

Refer: What affects enzyme action

Intracellular Enzymes

Intracellular chemicals are also known as endoenzymes. They are protein particles that work inside the cell. Also, they are the main reason behind most of the biological processes.

This type of enzyme aids the metabolic processes inside both prokaryotes and eukaryotes. For example, they can help both the photosynthesis process as well as cellular respiration inside the cell. Intracellular digestion also happens due to these enzymes.

Extracellular Enzymes

Most of the digestion in the alimentary canal is aided by the extracellular enzymes. An extracellular enzyme is a catalyst that is discharged and acts on the outer part of the cell. These enzymes are also termed exoenzymes. They assume an essential role during decay or decomposition. Moreover, they corrupt complex particles like cellulose and hemicellulose into smaller particles.

Also see: Decomposition process

Comparison between Intracellular and Extracellular Enzymes

The significant difference between intracellular and extracellular is that one acts inside the cell, and the other acts outside the cell. The table analyses the other differences between these enzymes.

Intracellular Enzymes

Extracellular Enzymes

They function within the cell.

They function outside the cell.

Most of the enzymes are intracellular.

Very few enzymes are extracellular.

Functions – Photosynthesis, DNA replication, Cellular respiration, Protein synthesis, Intracellular digestion, etc.

Functions – Extracellular digestion, Decomposition, etc.

Examples – DNA and RNA polymerase, ATP synthetase, etc. The lysosome and peroxisomes also contain intracellular enzymes.

Examples – Peptidase, amylase, trypsin, collagenase, pepsin, sucrase, maltase, kinases, etc.

Frequently Asked Questions

What are the activities of intracellular enzymes?

The Intracellular enzymes might dwell in the cytoplasmic liquid or be bound to cell organelles. There, they act for the synthesis of protein and DNA replication. They also aid the glycolysis process and Krebs cycle in the mitochondria. Also, they are present inside the chloroplast, helping in the photosynthetic pathway. Moreover, lysosomes (endoenzymes) play a significant role in intracellular digestion processes.

What are the similarities between intracellular and extracellular enzymes?

Both intracellular and extracellular enzymes are protein molecules made of amino acids. Also, they can be found in both prokaryotes as well as eukaryotes.

What is the role of extracellular enzymes?

Extracellular enzymes play a significant role in the decomposition process. Also, most digestive enzymes like trypsin, peptidase, pancreatic amylase are extracellular. Thus, they aid in the digestion process. Some of the microorganisms utilise exoenzymes and spread harmful pathogens. The microbial exoenzymes also aid in bioremediation. Some of them can be used as biofuels and in the paper industry.

Also Read: Role of digestive enzymes

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