Trypsin, calcium binding

Egg yolk phosvitin Trypsin ND Calcium-binding Jiang and Mine (2000)... 

Park, O., Swaisgood, H.E., and Allen, J.C. 1998. Calcium binding of phosphopeptides derived from hydrolysis of cts-casein or (3-casein using immobilized trypsin. J. Dairy Sci. 81, 2850-2857. 

Bode W, Schwager P (1975) The refined crystal structure of bovine -trypsin at 1.8 A resolution, II. Crystallographic refinement, calcium binding, benzamidine binding site and active site at pH 7.0. J Mol Biol 98 693-717... 

Fio. 18. Stereo view of the calcium-binding loop in trypsin including the calcium ion and internal water molecules. 

The calcium-binding sites in the protease domains of coagulation factors VII, IX, and X and protein C all have calcium affinities comparable to that in trypsin (241, 244-246). In the crystal structures of factors IX and X, no calcium ions could be identified, most likely due to the crystallization conditions because the calcium-binding site is present though not occupied (234). The crystal structure of factor VII in complex with tissue factor shows the presence of calcium in the... 

W. Bode and P. Schwagei J. Mol. Biol., 98, 693 (1975). The Refined Crystal Structure of Bovine Beta-Trypsin at 1.8 A Resolution. II. Crystallographic Refinement, Calcium Binding Site, Benzamidine Binding Site and Active Site at pH 7.0. 

BPTI, bovine pancreatic trypsin inhibitor MCBP, muscle calcium binding protein... 

Phospholipase 2 is a pancreatic enzyme that catalyses the hydrolysis of the 2-acyl linkage in phospholipids (21). The enzyme is secreted by the pancreas in an inactive form, prophospholipase 2 (PPLA2), which is activated by trypsin cleavage. It has been shown that both the enzyme (PLA2) and its zymogen bind Ca " ions with binding constants of 1-5 x 10 (22,23) and that this calcium binding is essential for... 

Fig. 3.13. Proportionality of the loss of accessible surface area to the molecular weight of proteins (from Janin, 1976). Different proteins insulin, rubredoxin, pancreatic trypsin inhibitor, HIPIP, calcium binding protein, ribonuclease S, lysozyme, staphylococcal nuclease, papain, chymotrypsin, concanavalin A, subtilisin, thermolysin, carboxypeptidase A.

Fig. 3.15. Variations and character of accessible surface area as a result of formation of secondary structures in six proteins pancreatic trypsin inhibitor (PTI), calcium binding protein (CBP), Bence-Jones protein REI (VIM), elastase (ELA), thermolysin (TLS), and carboxy-peptidase A (CPA). (A) Surface which remains accessible (B) surface which becomes buried. The partition, polar, charged, and nonpolar surface is indicated in all cases (according to Chothia, 1976).

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