What is the main difference between cow protein in human protein?

Answer 1

One of those phrases contains the letters C, O, and W and the other contains the letters H, U, M, A, and N.

The two phrases are, however, similar in that neither of them has any real meaning.

"Protein" is not a single thing that only differs based on what source it comes from, it's a class of compounds, which may differ wildly in structure or function.

It does make sense to talk about, for example. human insulin or bovine insulin; both of them are a type of protein, and one of them is found in people and the other is found in cows (I'll let you guess which is which). However, the differences between these two proteins is not the same as the differences between two other proteins found in the two species, such as bovine serum albumin vs. human serum albumin.

To go back to insulin: both bovine and human insulin contain 51 amino acid residues in two separate protein chains, but the bovine version differs from the human version by three substitutions: alanine for threonine at A8, valine for isoleucine at A10, and alanine for threonine at B30. At one time diabetics were treated using cow (or pig, which is even more similar, differing only at B30) insulin, but nowadays it is possible to produce human-identical insulin is produced via fermentation.

If you're curious: cat insulin differs from bovine insulin only in the substitution of histidine for asparagine at A18, meaning it's four residues removed from the human version, and dog insulin is identical to pig insulin.