English: Antithrombin reactive site loop sequence: The amino acid sequence of the reactive site loop of human antithrombin is shown. The reactive site loop comprises amino acid sequence numbers 377 to 400 (numbers shown below the above sequence) or amino acids P1 to P17 and P1' to P7' using the Schechter and Berger convention (number shown above the above sequence). The reactive bond is indicated by an arrow.