Peptides and proteins are fundamental components of the cells and they are responsible for carrying out vital biological functions in the body. Proteins give shape to body cells, for instance, they are responsible for responding to signals transmitted from the outside environment.
There are also certain types of peptides tasked with the function of regulating the activities of other certain molecules. In structure, proteins and molecules are very similar. They are all made up of chains of amino acids which are bonded together with peptide bonds. So what exactly distinguishes the two?
Difference in composition
The first difference between peptides and proteins lie on their actual composition. Proteins are made of only 20 different amino acids whereas peptides can be made of the 20 ‘protein amino’ acids in addition to other naturally occurring amino acids. Another basic difference between a peptide and a protein is the size of the chain or the number of amino acids contained in a peptide or a protein.
Proteins have longer chains compared to the peptides. Additionally, peptides and proteins differ significantly when considering their functionalities and the types of three dimensional structures they have. Some peptides may depict well defined dimensional structures while others may not have a well defined stable structure.
Differences in their functionalities
In most cases, peptides act as regulators of the activities of other molecules such as proteins. This regulatory role is achieved when the peptides interact with the target molecules. In this manner, we have peptides with antibiotic activity, hormonal activity and many more. Some peptides can be synthesized directly by the organism while others are the products of protein hydrolysis. Some of the peptides obtained by the breakdown of proteins have definite functions while others will continue to be broken down into smaller units.