LIST OF PARTICIPANTS 11 THERMOPHILIC HYDROLYTIC ENZYMES (PROTEINASES, AMYLASES) 17 Thermal Stability of Homologous Neutral Metalloendopeptidases in Thermo­ philic and Mesophilic Bacteria: Structural Considerations M. K. PANGBURN, P. L. LEVY, K. A. WALSH and H. NEURATH 19 The Structure and Stability of Thermolysin L. H. WEAVER, W. R. KESTER, K. F. TEN EYCK and B. W. MATTHEWS 31 Studies of the Inhibition of Thermolysin J. FEDER, N. AUFDERHEIDE and B. S. WILDI 41 Effect of EDTA on the Conformational Stability of Thermolysin A. FONTANA, E. BOCCU and F. M. VERONESE 55 Role of a Sulfhydryl Group in the Structure and Function of Alkaline Proteases from a Thermophilic Actinomycete K. MIZUSAWA and F. YOSHIDA 61 Partial Characterization of a Thermophilic Actinomycete Rennin S. LAXER, A. PINSKY and B. BARTOOV 67 Amylase Activity and Stability at High and Low Temperature Depending on Calcium and other Divalent Cations W. HEINEN and A. M. LAUWERS 77 Role of Calcium Ion in the Thermostability of a-Amylase Produced from Bacillus stearothermophilus K. YUTAN I 91 THERMOPHILIC DEHYDROGENASES 105 Thermophilic Glyceraldehyde-3-P Dehydrogenase R. E. AMELUNXEN and R. SINGLETON JR. 107 Glyceraldehyde 3-Phosphate Dehydrogenase from an Extreme Thermophile, Thermus aquaticus 121 J. D. HOCKING and J. I. HARRIS Thermal Properties of Glyceraldehyde 3-Phosphate Dehydrogenase from Escherichia coli A. FONTANA, C. GRANDI, E. BOCCU and F. M. VERONESE 135 Comparative Conformational Properties of Thermophilic and Mesophilic 6-Phosphogluconate Dehydrogenase F. M. VERONESE, C. GRANDI, E. BOCCU and A.