Do Chloroplasts Have Enzymes? 5 Facts You Should Know


Chloroplast is the most important cell organelle in plant cells which plays a very significant role in the photosynthesis process. Here we try to find out the answer to the question: do chloroplasts have enzymes or not?

With the concern to the question,the answer is yes, chloroplasts have different kinds of enzymes present in them. Most of the chloroplasts enzymes are involved in the photosynthesis process.

As the chloroplast enzymes play the major role in the photosynthesis process there are also some enzymes found which are involved in the process of removal of non-necessary by-products of those following reactions. 

Chlorophyll is the primary site of light absorption in chloroplast structure. Many enzymes are found which are involved with the metabolism and degradation of these chlorophyll substances inside the thylakoid of the chloroplast organelle. 

Do chloroplasts have enzymes

Do chloroplasts have enzymes? From Wikimedia commons

Do all chloroplasts have enzymes?

Yes, all chloroplasts have enzymes in their structure. The enzymes are the primary substances which involve directly with every phase of the photosynthesis process. Hence all functional chloroplasts contain different enzymes in them.

There are some key enzymes which are present in all chloroplasts and intimately involved in different metabolic processes of chloroplasts. RuBisCO is most important enzyme of chloroplasts which catalyses the photosynthesis process. It is also known as the marker enzyme of chloroplast organelle.

Other than RuBisCO, there are some enzymes like FBPase or Fructose bisphosphatase, SBPase or Sedoheptulose-bisphosphatase, Fructose-1,6-bisphosphate aldolase, Phosphoenolpyruvate carboxylase, Ribose-5-phosphate isomerase, etc are found which are involved in calvin cycle process of photosynthesis and are present in every chloroplasts.

There are also some chloroplast enzymes found  such as chlorophyllase, POD, LOX, Peroxidases, Catalases, etc which are involved in metabolism of chlorophyll and present in all chloroplasts structures.

Where are chloroplast enzymes located?

The most chloroplast enzymes are located in the thylakoid membrane or in the stroma of the chloroplasts. As stroma is the primary site of the photosynthesis process and most of the enzymes are required in this metabolism, hence several chloroplast enzymes are located in the stroma of the chloroplasts

One of the most important chloroplast enzymes, RuBisCO, is located in the stroma of the chloroplast organelle. 

Metabolic enzymes like ATPase are located in the thylakoid membrane of chloroplasts. Other enzymes related to chlorophyll synthesis such as chlorophyllase, Peroxidases, Catalases, etc located at the thylakoid membrane of the chloroplasts.

Chloroplast enzyme role

The main role of chloroplast enzymes is to facilitate the photosynthesis process. Here we mention some mosy common functions or role of enzymes present in chloroplasts structure.

Helps in carbon dioxide absorbance

In photosynthesis process one of the most important step is absorbance of inorganic carbon dioxide from the atmosphere. The enzyme RuBisCO or Ribulose-1,5-bisphosphate carboxylase-oxygenase helps and also controls the amount of carbon dioxide absorbance, hence influence the photosynthesis process intensely.

Helps in fixation of carbon

Different chloroplast enzymes along RuBisCO enzyme, facilitates fixation of carbon during photosynthesis. In this way the inorganic carbon converts into organic carbon substances such as glucose molecules.

Catalyses various metabolic reactions

During the process of photosynthesis different chloroplast enzymes catalizes various metabolic reactions. In light indipendent step of Photosynthesis the Enzyme PGK catalyses reversable transfer of phosphate group, PRK catalyses phosphorylation reactions. 

Influence growth factors

The enzyme SBPase or Sedoheptulose-bisphosphatase controls the amount of produced carbohydrates in chloroplasts, hence it also influence growth of the plant body.

Faciliates chlorophyll formation

Not only the photosynthetic enzymes, chloroplasts also consist enzymes which Faciliates chlorophyll formation in the thylakoid membrane. Chlorophyllase is a enzyme mostly known for its role in chlorohyll synthesis. 

Controls degradation of chlorophyll

The chloroplasts also have enzymes which controls the degradation of chlorophyll pigment during sedding or autumn season. The enzymes Peroxidases, Catalases, etc facilitates degradation of chlorophyll pigment at the time of ripening of that leaf.

So here we mention some most common roles of enzymes present in chloroplast structure.

Photosynthesis process in chloroplasts from dreamstime.com

Which enzymes are present in chloroplast?

There are several enzymes present in chloroplasts, such as Ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO), FBPase (Fructose bisphosphatase), Sedoheptulose-bisphosphatase (SBPase), PRK, chlorophyllase, POD,  LOX, Peroxidases,  Catalases, etc.

These are some most common enzymes present in chloroplast organelle. In between them RuBisCO or Ribulose-1,5-bisphosphate carboxylase-oxygenase, FBPase or Fructose bisphosphatase , SBPase or Sedoheptulose-bisphosphatase, PRK, etc are involved in the photosynthesis process. Other enzymes like chlorophyllase, POD,  LOX, Peroxidases,  Catalases, etc are involved in the chlorophyll metabolism process.

Which enzyme is maximum in chloroplast?

In the stroma of the chloroplasts 50% of soluble protein is RuBisCO enzyme. It is present maximum in chloroplasts. The concentration of RuBisCO enzyme in a chloroplast is almost about 240 mg ml–1. 

For its contribution in the metabolism of photosynthesis process and presence in huge amount specifically in chloroplasts, the Ribulose-1,5-bisphosphate carboxylase-oxygenase or  RuBisCO enzyme is refer as the marker enzyme (enzymes which serve as biomarkers of an particular cell organelle, specifically found in that part of cell) chloroplasts organelle.

Do chloroplasts have enzymes ? RuBisCO enzyme from Wikimedia commons

Which enzyme is less in chloroplast?

There are many enzymes related to the metabolism of chlorophyll such as POD,  LOX, Peroxidases, Catalases, etc. These enzymes are present in less amounts in chloroplasts but highly influence the metabolism of chlorophyll substances.

Structure of chloroplast from Wikimedia commons

Summary

As a whole we can say that chloroplasts are the primary site of the photosynthesis process. The chloroplast enzymes are involved together in different metabolism processes including photosynthesis. Here we try to find out the answer to the question: do chloroplasts have enzymes or not? Hope we successfully demonstrate the answer and also discuss about 5 common facts related to the enzymes of chloroplasts.

Piyali Das

Hello, I am Piyali Das, pursuing my Post Graduation in Zoology from Calcutta University. I am very passionate on Academic Article writing. My aim is to explain complex things in simple way through my writings for the readers. We can connect through LinkedIn https://www.linkedin.com/in/piyali-das-484019216 .

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