Do Prokaryotes Have Enzymes: 9 Interesting Facts


In this article, we get know about 9+ Important Facts regarding ‘Do Prokaryotes Have Enzymes?’, along with their origin, characteristics, functions and examples.

The prokaryotic cell was originally regarded to as a “bag of enzymes” with little to no internal compartmentalization. The majority of actions required for life, according to this view, were the consequence of unexpected molecular collisions comprising substrates, cofactors, and cytosolic enzymes.

Let us discuss some facts and try to understand “Do Prokaryotes Have Enzymes

  • Where the enzymes are located in prokaryotes?
  • How do prokaryotes use enzymes?
  • What enzymes are involved in prokaryotes replication?
  • Why do prokaryotes bacteria have restriction enzymes?
  • How do prokaryotes produce enzymes?
  • Which enzyme is found only in prokaryotes?
  • How to extract enzymes from prokaryotes?
  • Which enzyme is not found in prokaryotes?
  • Does prokaryotic cell membrane have enzymes?
  • Do prokaryotes and eukaryotes have the same enzymes?

Many distinct types of enzymes are produced by prokaryotes, and even a single strain can produce a variety of cellular or secreted enzymes.

Ex:

  • Virtually all chemical reactions that happen inside of cells are considerably sped up by enzymes, which are biological molecules. DNA Polymerases I, DNA polymerases II, and DNA polymerases III are the three main types of polymerases found in prokaryotes.
  • DNA polymerase III is currently understood to be the enzyme necessary for DNA synthesis; DNA polymerase I, along with DNA pol II, is mostly needed for repair and serves as an important auxiliary enzyme in DNA replication.

Prokaryotic cell membranes include respiratory enzymes, help with DNA replication, and serve as attachment sites for bacterial flagella. cells’ cytoplasm- Ribosomes and other functional granules are found in the cytoplasm of prokaryotic cells, which are part of the organism..

Where the enzymes are located in prokaryotes?

Prokaryotes are microscopic creatures (0.5–1.5 pm). The cell is surrounded by plasma membrane. A significant number of enzymes, such as those necessary for cellular respiration, are found in the plasma membrane. When of the lateral variety, mesosomes—an ingrowth of plasma membrane—also include respiration enzymes and are referred to as chondroids.

Ex: Mesosomes are the location of respiratory action in bacteria. Folded invaginations called mesosomes are seen in bacterial cell membranes. They increase the amount of surface area needed for breathing. They have enzymes for respiration. It is where breathing takes place.

  • Mesosomes, or folded invaginations of the plasma membrane, are the plasma membrane’s expansions into the cell.
  • The vesicles, tubules, and lamella that make up these extensions are all possible. They perform a variety of tasks, such as forming the cell wall, replicating DNA, and distributing it to daughter cells.
  • By giving the oxidative enzymes a membrane to generate a gradient, they assist respiration. By expanding the plasma membrane’s surface area, it also aids in secretion.

Characteristics

  • The cell membranes of eukaryotes and bacteria share many structural similarities; however, bacterial membranes typically only contain saturated (SFA) or monounsaturated fatty acids (MUFA) (rarely PUFA-polyunsaturated fatty acids) and do not include sterols.
  • In bacteria, the cell membranes are a crucial component. They are constructed of substances chemically unique to nature. Some of our most significant antibiotics work on the cell membrane.
  • Membrane-bound organelles like plastids and mitochondria are absent from bacterial cells. However, their plasma membrane is folded into lysosomes, which are known as bacterial mitochondria and carry respiratory enzymes.
  • Single-celled creatures called prokaryotes include bacteria and archaea. The multiple membrane-bound organelles found in eukaryotic cells are also absent from these cells. The prokaryotic cells contain the respiratory enzyme, and the membrane facilitates DNA replication.

How do prokaryotes use enzymes?

Prokaryotes produce their secreted proteins on ribosomes that are attached to the plasma membrane’s cytoplasmic surface.

Ex:

Amongst three prokaryotic enzymes i.e., Pol I, II and III, it is now understood that DNA polymerase III is the enzyme necessary for DNA synthesis; DNA polymerase I, along with DNA polymerase II, is mostly needed for repair and serves as an important accessory enzyme in DNA replication.

do prokaryotes have enzymes
Functional DNA polymerase I domains from Wikipedia

The replication of DNA can be summed up as follows:

  1. At the start of replication, DNA unwinds.
  2. The DNA-forming replication forks are opened by the helicase and expanded in both directions.
  3. To stop DNA from rewinding, single-strand binding (SSB) proteins cover the DNA adjacent to the replication fork.
  4. Topoisomerase attaches to the region prior to the replication fork to stop supercoiling.
  5. The enzyme Primase creates RNA primers that work with DNA strands.
  6. DNA polymerase III begins incorporating nucleotides into the primer’s 3′-OH end.
  7. Both the lagging and leading strands continue to elongate.
  8. The RNA primers are removed by the exonuclease action.
  9. DNA pol I incorporates dNTPs to fill up gaps.
  10. DNA ligase helps to create phosphodiester connections by bridging the gap between the two DNA segments.

What enzymes are involved in prokaryotes replication?

Due to the prokaryotic genome’s limited size and the abundance of mutations, DNA replication in these organisms has been thoroughly studied. One circular chromosome of E. coli contains 4.6 million bps, and the entire chromosome replicates in around 42 minutes, beginning at one location and moving in both directions around the circle.

do prokaryotes have enzymes
Replisome from E. coli with a loop in the lagging strand of DNA from Wikipedia

Prokaryotic DNA Replication: Enzymes and Their Function

Many structural proteins and enzymes are used in DNA replication, and each one is essential to the process.

Enzyme/proteinSpecific Function
DNA polymerase IDNA polymerase exhibits exonuclease activity. A DNA pol I, after eliminating the RNA primer, substitute it with primer to already generated DNA.
DNA polymerase IIRepair capability
DNA pol IIIThe primary enzyme for adding nucleotides in the 5′-3′ direction is DNA pol III.
HelicaseBy rupturing the hydrogen bonds between the nitrogenous bases, the helicase opens the DNA helix.
LigaseConstructs a single continuous DNA strand by filling up the spaces between the Okazaki fragments.
PrimaseCreates the RNA primers necessary for replication to begin.
Sliding ClampAids in maintaining the position of the DNA polymerase during the addition of nucleotides.
TopoisomeraseReduces stress on DNA during unwinding by breaking the DNA and then resealing it.
Single-strand binding (SSB)  proteinsIn order to prevent DNA from looping back on itself, single-strand binding proteins (SSB) bond to single-stranded DNA.
The table below lists the roles played by each of the bacterial DNA replication-related enzymes.

Why do prokaryotes bacteria have restriction enzymes?

In prokaryotes, restriction enzymes prevent foreign DNA, such as bacteriophage DNA in bacteria, from multiplying. The bacterium is thus shielded from bacteriophage attack by the restriction enzyme. It is a way for bacterial cells to defend themselves.

  • Ex: Restrictions enzymes are found in bacteria (and other prokaryotes). They locate specific DNA sequences known as restriction sites and adhere to them. Each restriction enzyme only recognises one or a few restriction sites.
  • This is because an enzyme known as methylase significantly methylates the DNA of eukaryotes. Methylation protects DNA against the effects of restriction enzymes. These enzymes are present in prokaryotic cells wherein they help to prevent the invasion of viral DNA.

How do prokaryotes produce enzymes?

Some prokaryotes have unique enzymes and metabolic pathways that enable them to break down substances that contain sulphur or nitrogen. Important functions for prokaryotes are played in the movement of nutrients across ecosystems.

Prokaryotic cells’ cytoplasm is where protein synthesis, which entails the two processes of transcription and translation, occurs. During transcription, RNA polymerase converts operons, a type of DNA segment, to mRNA in the cytoplasm.

Which enzyme is found only in prokaryotes?

Since eukaryotes are unable to synthesize nitrogenase, they are unable to fix atmospheric nitrogen. Nitrogenase is only found in the plasmids of prokaryotes.

  • The enzyme nitrogenase is in charge of converting dinitrogen into ammonia. It is a catalytic enzyme that is essential for the nitrogen fixation process.
  • This enzyme is composed of molybdenum iron protein and is oxygen-sensitive.
  • “For this enzyme to function, a very high energy intake and anaerobic conditions are necessary” (without the presence of oxygen).

 Activation of Nitrogenase:

  • Bacteria, cyanobacteria, and symbiotic bacteria are responsible for biological nitrogen fixation.
  • In symbiotic relationships, bacteria exchange carbohydrates for fixed nitrogen from their hosts.
  • During this process, atmospheric nitrogen is reduced to ammonia in the presence of nitrogen.
  • Nitrogenase is activated by molybdenum..

 

How to extract enzymes from prokaryotes?

It is common exercise to either allow the enzymes to be produced by the autolysis of the cell membranes or cell walls in the culture broth or to speed up the lysis of the cells by applying a chemical that promotes lysis, such as sodium dodecyl sulphate (SDS).

Process:

  1. The alternative methods that have been suggested include those that involves the mechanical destruction of the cell walls through the use of ultrasonication, trituration, the French press method along with freezing and thawing, as well as the method that involves the enzymatic destruction of the cell walls through the use of lysozyme.
  2. These strategies are difficult to implement in industrial practise, and none of the aforementioned techniques can achieve high efficiency. Only a few of the complex techniques, such the gel-filtration and dialysis techniques, are used in laboratories.
  3. Solutions containing urea can be used to extract the enzymes from bacteria and fungi. The liquid cultured cells are collected by centrifugation or filtration, cleaned with water, and employed in the subsequent procedures. Naturally, the innovation can use either fresh cells or dry cells.
  4. Several industrial processes use certain enzymes as organic catalysts, and these enzymes are of particular interest. Microbial enzymes, which are generated from diverse microorganisms, are widely acknowledged as superior enzymes, especially for commercial uses in industries.

Which enzyme is not found in prokaryotes?

No, lysosomes are not present in bacterial cells. This is because golgi bodies, which are membrane-bound organelles unique to eukaryotes, and the endoplasmic reticulum combine to generate lysosomes.

Does prokaryotic cell membrane have enzymes?

The NADH dehydrogenase complex, different cytochromes, the enzyme cytochrome oxidase complex, and coenzyme Q are the enzymes involved in prokaryotic cellular respiration.

Do prokaryotes and eukaryotes have the same enzymes?

Both eukaryotes and prokaryotes have these substantial, multisubunit RNAP enzymes. Because eukaryotes’ transcription is more tightly controlled than that of prokaryotes, they have been able to develop into multicellular creatures with unique cell tissues and functions.

do prokaryotes have enzymes
Eukaryotes and prokaryotes are compared from Wikipedia

Conclusion

In the above article, we studied about prokaryotic enzymes: origin, functions, types and structures. Their role in prokaryotic DNA replication and respiration. The extraction of prokaryotic enzymes is also studied.

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