关于IFN-α2b: At least 23 different variants of IFN-α are known.The individual proteins have molecular masses between 19-26kDa and consist of proteins with lengths of 156-166 and 172 amino acids.All IFN-α subtypes possess a common conserved sequence region between amino acid positions 115-151 while the amino-terminal ends are variable.Many IFN-α subtypes differ in their sequences by only one or two positions.Naturally occurring variants also include proteins that are truncated by 10 amino acids at the carboxyl-terminal end.