Interferon Alpha 2-a (PEG) vs 2-b,(Bes) exactly what's the diff?

[EPguy]

I posted this image recently, but here it's in a new context.

For those who are curious exactly how 2-a and 2-b IFNs differ (I posted inside another thread before but here's a new post on it):

prospecbio.com/interferon-a...

"The difference between IFNA2A and IFNA2B is in the amino acid present at position 23. IFN-alpha 2a has a lysine at that position 23 while IFN-alpha 2b has arginine."

In the Besremi image here, the green part is the IFN, and this could be either 2a or 2b. Besremi chose 2b (with Arginine) , Pegasys chose 2a (with Lysine).

Does this matter, who knows. It sure does in Jak2 where switching V and F at 617 (Jak2-v617f) makes a life changing diff for us. All these being switched are amino acids, but these are not really comparable since one is a med and the other is a gene.

Did Besremi select the best one? Why did they not use the same one as PEG?

One good thing to know is there are many types of IFN, all the stuff after IFN-(α2-) means it's a quite specific type, whether a or b. For example there are at least two other Greek letters , β, γ, and more numbers than just "2" that don't apply to us. Yes there is even a "2c" that we don't use. So the IFNs we use have been selected as particularly suited for our purpose.

A second and apparently more important difference, the blue pegylation, differs in how it's attached to the IFN as I've posted before. There is plenty of info on this feature and its ability to stretch dosing intervals, but near none of the type of IFN.