What is the difference between polypeptide and protein?

Answer 1

First, it is important to know that all proteins are technically polypeptides, although in general scientists consider polypeptides molecules consisting of one strand of amino acids chemically bound to one another that have no special or unique properties. It would be very difficult or impossible to find a degreed and professional scientist who considers all polypeptides proteins.

One difference between what is called a "polypeptide" and a "protein" is based on the number of amino acids each one contains. A chain of amino acids that contains relatively few amino acids compared to known proteins is a "polypeptide." The second most important distinction between how the two words are used is that scientists normally reserve the word "protein" for molecules consisting entirely or nearly entirely of amino acids that exhibit specialized physical or chemical properties, or both. For example, hemoglobin is considered a "protein" because it is specialized to carry the oxygen in our red blood cells. Keratin is another protein that serves as a structural material in our skin and is the material of which hair is made. On the other hand Aspartame, the artificial sweetener, is a polypeptide since it only consists of three amino acids chemically bound to one another, thus it is too small to be called a protein. I can see how one might argue that it is a protein because it has a powerful sweet taste, however there are several other chemical compounds that are not sugars that also have a powerful sweet taste. (What would otherwise be the carboxylic acid end of aspartame has been changed to its methyl ester.)

Answer 2

Briefly, an amino acid are the monomers, the building blocks upon which the protein is based upon. Two amino acids constitute a dipeptide, while three or more create a polypeptide. The union of two or more polypeptides (quaternary structure) results in a protein.

Answer 3

A peptide is a smaller chain of some amino acids (from di-, tri, tetra-peptides and up to 5 or 10) and a polypeptide is a much longer longer chain of more (=poly) amino acids.

Answer 4

Polypetide is a chain of aminoacids more than 10 in number but a protein has atleast 20 amino acids as there are 20 to 25 types of amino acids in a protein. second difference is that there are about 170 types of amino acids which may join by peptide bond to form polypeptide but a protein has not more than 20 types among these 170 types. so others may be included in polypeptide but not in a protein. in short all proteins are polypeptides but all polypeptides are not proteins.

Answer 5

All protein is made up of different length of polypeptide (imagine a chain made up of many strings) chains, the main difference is active or stable protein is something made after "proper folding" of polypeptide chain (amino acids on the string)

Answer 6

Size. Proteins are made of many more peptides than polypeptides are.

Answer 7

A peptide is any two or more amino acids that are put together by peptide bond. A protein is a functional, polypeptide chain composed of at least around fifty amino acids put together.

Answer 8

man i need to know what the awnser is lol