The key difference between proteinase K and protease is that proteinase K is useful in digesting proteins and removing contamination from nucleic acid preparations, whereas protease is useful in biological functions such as digestion of ingested proteins, protein catabolism, and cell signaling.
Proteinase K and protease are two types of protein-cleaving enzymes. In other words, proteinase K and protease can cleave peptide bonds in proteins.
CONTENTS
1. Overview and Key Difference
2. What is Proteinase K
3. What Protease
4. Proteinase K vs Protease in Tabular Form
5. Summary
What is Proteinase K?
Proteinase K is a broad-spectrum serine protease enzyme. It was discovered in 1974 and was extracted from fugus Engyodontium album species. This enzyme can digest keratin in hair, which leads to its name proteinase K (where K stands for keratin). During this digestion, the site where the cleavage occurs is the peptide bond that occurs adjacent to the carboxyl group of aliphatic and aromatic amino acids having blocked alpha-amino groups. Moreover, this enzyme is useful because of its wide spectrum of specificity.
When considering the activity of proteinase K enzyme activity, it is activated by calcium. It can digest proteins, mainly hydrophobic amino acids such as aliphatic, aromatic, and other hydrophobic amino acids. However, calcium ions can contribute to the stability of the enzyme though these ions do not affect the activity of the enzyme. Moreover, the enzyme can digest the proteins completely if the incubation time is long and if the enzyme concentration is high enough for the digestion process. If we remove the calcium ions in the reaction mixture, the stability of the enzyme reduces (however, the proteolytic activity remains unchanged).
There are two binding sites for calcium ions in this enzyme. These sites are located near the active center of the enzyme, but they are not directly involved in the enzymatic activity. Usually, the proteinase K enzyme can digest the proteins that can contaminate nucleic acid preparations; thus, we need to use this enzyme in the purification of the nucleic acid samples in the presence of EDTA to reduce metal-ion dependent enzymes, e.g. nuclease).
What is Protease?
Protease is an enzyme catalyzing proteolysis. It is also named peptidase or proteinase. It can increase the rate of proteolysis reaction where proteins are broken down into small polypeptides or into single amino acids. The enzyme does this catalysis by cleaving the peptide bonds within the proteins through hydrolysis reaction (where the water breaks bonds).
This protease enzyme is involved in many different biological functions, including digestion of ingested proteins, protein catabolism, and cell signaling.
There are seven different types of protease enzymes as follows:
- Serine protease
- Cysteine protease
- Threonine protease
- Aspartic protease
- Glutamic protease
- Metalloprotease
- Asparagine peptide lyase
What is the Difference Between Proteinase K and Protease?
Proteinase K and protease are two types of protein-cleaving enzymes. In other words, proteinase K and protease can cleave peptide bonds in proteins. The key difference between proteinase K and protease is that proteinase K is useful in digesting proteins and removing contamination from nucleic acid preparations, whereas protease is useful in biological functions such as digestion of ingested proteins, protein catabolism, and cell signaling.
The below infographic tabulates the differences between proteinase K and protease.
Summary – Proteinase K vs Protease
Proteinase K and protease are two types of protein-cleaving enzymes. The key difference between proteinase K and protease is that proteinase K is useful in digesting proteins and removing contamination from nucleic acid preparations, whereas protease is useful in biological functions such as digestion of ingested proteins, protein catabolism, and cell signaling.
Reference:
1. Ruggeri, Christine. “The Enzyme That Makes Protein & Amino Acids Tick.” Dr. Axe, 9 Sept. 2020.
Image Courtesy:
1. “PDB 1pek EBI” By Jawahar Swaminathan and MSD staff at the European Bioinformatics Institute – (Public Domain) via Commons Wikimedia
2. “TEV protease summary” -Thomas, Shafee, (2014). “Evolvability of a viral protease: experimental evolution of catalysis, robustness and specificity”. PhD Thesis. University of Cambridge. (CC BY 4.0) via Commons Wikimedia