Dual Nature of RuBisCo ?


While studying photosynthesis you must have obviously come across this word "RuBisCo". It's not a huge topic but I think you should know its role and does it show dual nature. Even if you don't what RuBisCo stands for, stay tuned to know what RuBisCo is.

Does RuBisCo show dual nature ? 

So let me tell you first that RuBisCo stands for Ribulose Biphosphate Carboxylase Oxygenase. As the name itself have "carboxylase" and "oxygenase" you know it will show dual nature, but what does it exactly show dual nature in ?

RuBisCo catalyses the carboxylation of RUBP and also the it can oxygenate it as well. This is just the basics but here comes the tricky part. When RuBisCo carries out carboxylation of RUBP, the product formed is going to be PGA (Phosoglyceric acid) which is a 3C compound and if this is the end product there is normal photosynthesis taking place which is fine. This is not just it, we know it also shows another nature which is oxygenation of RUBP.

If RuBisCo oxygenated RuBP, phosphoglucolic acid which is a 2C is the end product so there is photorespiration taking place and photosynthesis is obstructed.

Just so if you don't know the difference between photosynthesis and photorespiration I will explain it to you in brief here. So, when there is direct energy coming from the sunlight, the plant or maybe some bacteria also, make glucose with the help of carbon dioxide and water in the presence of sunlight is called photosynthesis. Where as photorespiration means the process of respiration which takes place where carbon dioxide is given out which is the opposite process of photosynthesis.

Hence, to avoid this photorespiration taking place some plants have developed a special anatomy of leaf called the Kranz anatomy and this is in the C4 plants.

What is RuBisCo ? 

For all those who don't know what RuBisCo is as I mentioned above RuBisCo stands for Ribulose Biphosphate Carboxylase Oxygenase. It can also be termed as Rubisco, rubisco, RuBPCase or even RuBPco, so don't get confused when you see these terms.

RuBisCo is an enzyme which is the first product evolved in the Calvin cycle, in carbon fixation and then oxygenation takes place and photorespiration occurs. This is the main enzyme in Calvin cycle. This enzyme is available in large quantity on earth. The role of RuBisCo depends upon how much is the concentration of CO2 and O2 in the mesophyll cells. If the concentration of CO2 is high then PGA (Phosoglyceric acid) is formed and if the concentration of O2 is high, phosphoglucolic acid is formed. This effect is called the Warbug effect.

Here is a simple image you can refer to for better understanding:


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