Thermolysin, thermal stability

Thermolysin is a zinc-dependent proteinase (Mr = 34.6K) that requires Ca for optimal thermal stability. The thermolysin (3TLN) crystal structure contains four bound Ca ions. Two of these lie only 3.8 A... 

Thermolysin is a zinc metallo enzyme which binds Ca2+ ions. It consists of a single polypeptide chain of M.W. 34600 containing 316 amino acid residues. Four Ca2+ ions per molecule give thermal stability to the enzyme. The crystal structure of both Ln3+ substituted and unsubstituted enzyme has been determined [54],... 

The thermal stability of thermolysin, a peptidase from the thermo-phillic bacterium Bacillus thermoproteolyticus, is apparently conferred by calcium bound to the enzyme (194), which has a molecular weight of 35,000 (195), and binds one mole of zinc (195) and three moles of calcium per mole of protein (196). Thermolysin contains no non-protein constituents (197) and consists of a single peptide chain containing neither cysteine nor cystine (197). Thermolysin has a high content of aspartic... 

The thermal analysis by DSC was carried out for thermolysin crystal suspensions in which crystal growth was on progress. As a result, it was found that three ups of thermolysin differing in the thermal stability exist. Each group was assigned to monomers, oligomers, and crystals, respectively. The denaturation temperature of... 

The ability of Ca2+ to crosslink groups and so stabilize proteins against thermal denaturation or hydrolytic attack is well illustrated by thermolysin, which involves four Ca2+ and a catalytic Zn2+. The function of the calcium is to stabilize the protein structure.404 Calcium also protects surface protein of the neural retina from tryptic cleavage.405... 

Thermolysin. Bacillus thermoproteolyticus neu -tral proteinase, E.C. 3.4.24.4. Proteolytic enzyme of mol wt 37,500 that hydrolyzes protein bonds on the JV-terminal side of hydrophobic amino acid residues. Contains a zinc atom essentia] for activity and four Ca2+ ioos essentia] for thermal and conformational stability. Isolo from Bacillus thermopro-leolyticus S. Endo, J. Ferment. Technol. 40, 346 (1962). Properties and amino acid composition Y. Ohta ei of., J. Biol. Chem. 241, 5919 (1966). Site of enzymatic hydrolysis Y. Ohta, Y. Ogura, J. Biochem. 58, 607 (1965). Substrate specificity studies H. Matsubara ei al.. Biochem. Biophys. Res. Commun. 21, 242 (1965) 24, 427 (1966) K. Morihara, H. Tsuzuki, Biochim. Biophys. Acta 118, 215 (1966). Stability studies Y. Ohta, J. Biol. Chem. 242, 509 (1967). Inhibition studies H. Matsubara et al., Biochem. Biophys. Res. Commun. 34, 719 (1969) J. Murphy et al., Arch. Biochem. Biophys. 202, 405 (1980). Purification H. Matsubara,... 

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