Mapping the active site of bovine thrombin, factor IXa, factor Xa, factor XIa, factor XIIa, plasma kallikrein and trypsin with amino acid and peptide thioesters: Development of new sensitive substrates - McRae, B J; Kurachi, K; Heimark, R L; Fujikawa, K; Davie, E W; Powers, J C (Biochemistry, 1981)