Difference Between Purine vs Pyrimidine
Today we’re going to lay out the specific difference between purine and pyrimidine and explain how the two often get confused when being used as part of the same sentence. These compound organic entities are both heteroyclic and aromatic. And they’re both used to establish the foundation aspects that comprise DNA and RNA. This just means that they’re building components.
How they differ is that they’re used to build different “parts” of RNA and DNA architecture. It’s understandable that they get mixed up, but by the end of today’s post, you’re going to see what makes them totally separate entities.
Definition of Purine
Purine is: “A compound that is both crystalline and colourless in appearance, featuring basic properties. With the addition of oxygen, it becomes uric acid.”
This crystalline compound establishes half of the nucleobases (a nucleobase is a structure that something is built upon) that form the foundational framework of DNA and RNA. One of the key giveaways that pyrimidine and purine are different lies in the fact that purine is surrounded by a pyrimidine ring (that has in turn been synchronised with a ring made out of imidazole).
This immediately means, then, that the two are entirely separate entities. Their separation can be further embellished due to their different boiling points (purine’s is much higher). Interestingly, despite them not being the same at a molecular level, the difference between purines and pyrimidines is incredibly small, at least operationally. They both ultimately serve almost precisely the same function, they’re just formed differently.
Definition of Pyrimidine
Pyrimidine is: “A crystalline compound that is colourless and features basic properties.”
If you only had the descriptions alone to work with when delving into the purine vs pyrimidine debate, it’d be entirely understandable if you couldn’t separate one from the other. The descriptions, after all, are near enough identical. What does pyrimidine look like at a molecular level, though? Well, pyrimidines are much smaller than purines. In conjunction with this, they consist entirely of only one carbon ring.
So, if purine is used to manifest DNA and RNA, and it’s made via the integration of a pyrimidine ring, and if pyrimidine is also used to create these crucial building blocks of life, albeit being made with one singular carbon ring, then what’s the specific role of pyrimidine vs purine?
It turns out that it’s almost the same. Purine is used to create two out of the four components necessary for DNA and RNA manifestation, whereas pyrimidine creates the other two. So they serve almost exactly the same purpose.
It’s just that one does it from one side of the fence, if you like, and the other fulfils it from the opposite side. When combined together, they both achieve their ultimate goal and establish fully-fledged DNA and RNA structures.
Main Differences Between Purine vs Pyrimidine
We’re now going to provide you with a quick reference table that you can come back to any time you wish for a memory revamp on these two vital organic compounds.
| Basis of Comparison | Purine | Pyrimidine |
| What does it look like? | Enveloped by an imidazole and pyrimidine ring | Surrounded by a carbon ring |
| Size | Large | Small |
| Associated Nucleobases | Guanine, adenine | Uracil, cytosine, thymine |
| What point does it melt at | 214 degrees | 20 – 22 degrees |
| Purpose | For producing DNA, proteins, starches, RNA, and regulating enzymes and cell signalling | For producing DNA, proteins, starches, RNA, and regulating enzymes and cell signalling |
Difference Between Purine and Pyrimidine: Conclusion
Comparing purine vs pyrimidine has been the source of endless confusion for many people in the scientific world before now, but after reading through today’s post, you now hopefully understand why the two are separate entities.
Though the intricate details might be difficult to remember, you can still easily sum up the difference by saying, “Purine creates one half of RNA and DNA blocks. Pyrimidine creates the other.” Without diving into great detail, that sentence alone essentially describes their function in a very basic and easy to remember fashion. Don’t forget to come back to our quick reference table any time you need a refresh.
