There can be several types of glycosylation. They are N-linked glycosylation O-linked glycosylation, phosphoserine glycosylation, etc. Generally, during glycosylation, the carbonyl part of the sugar reacts with the amine or hydroxyl group of the protein.
What are the Similarities Between Glycation and Glycosylation?
- Both glycation and glycosylation add sugars to proteins.
- During both processes, covalent bonds are built up between the molecules.
- Both are cellular processes.
- Moreover, both processes affect the functionality of a protein.
What is the Difference Between Glycation and Glycosylation?
Glycation is a non-enzymatic process that covalently adds free sugars to protein while glycosylation is an enzymatic post-translational modification process occurring in the endoplasmic reticulum and Golgi apparatus, which produces a functional protein. Therefore, we can consider this as the key difference between glycation and glycosylation. Furthermore, glycation is a spontaneous process; hence, it is not regulated by an enzyme. But, glycosylation is a fully enzyme-regulated process. Thus, this is also a difference between glycation and glycosylation.
Moreover, glycation reduces the stability and functionality of proteins. However, glycosylation produces a functional protein through the addition of sugar molecules. In addition, a further difference between glycation and glycosylation is that the glycation adds glucose, fructose or galactose to proteins while glycosylation adds xylose, fucose, mannose or glycans to proteins. Most importantly, glycosylation increases protein stability while glycation reduces protein stability. So, this is another significant difference between glycation and glycosylation.
The below infographic presents more information regarding the difference between glycation and glycosylation.
Summary – Glycation vs Glycosylation
Both glycation and glycosylation are two processes that add sugar to proteins. Glycation is a non-enzymatic spontaneous process that takes place in the bloodstream. In contrast, glycosylation is an enzyme-mediated process that takes place in the Golgi apparatus and endoplasmic reticulum under post-translational modifications. Furthermore, glycation reduces the stability and functionality of a protein due to the addition of sugars whilst glycosylation converts an immature protein into a functional protein due to the addition of sugars. So, this is a summary of the difference between glycation and glycosylation.
1. “Glycosylation.” Thermo Fisher Scientific – US, Available here.
2. Takahashi, Motoko. “Glycation of Proteins.” SpringerLink, Springer, Tokyo, 1 Jan. 1970, Available here.