“… heparin … papain specifically; this interaction induces an increase of its α-helix content and stabilizes the enzyme structure even at alkaline pH (Almeida, P. C., Nantes, …. C. A., Júdice, W. A. S., Chagas, J. R., Juliano, L., Nader, H. B., and Tersariol, I. L. S. (1999) J. Biol.”