Structural study on pepsin stability in the presence

Pepsin (E. C. 3. 4. 23. 1) is a juise gastric aspartic proteinase S. It belongs to hydrolaes family. It is structure is consis of two lobes that they are similar in size and folding. It consis of a single polypeptide chain of molecular weight 34644 Da and 327 amini acid. Pepsin contais 1. 2% basic residues، 13. 1% acidic residues، 46. 5% polar residues، 39. 2% hydrophobic residues. S tructural stability of pepsin was investigated by UV-VIS spectrophotometry and spectrophlorimetry. Spectral measurements were made at pH 2 and temperatures between 30 and 100 ºC. It was observed that (1) enzyme stability considerable is high، (2) enzyme stability decreases in the presence of urea at pH 2. (3) decrease of thermodynamic parameters and in the presense of urea. (4) increase of flurense intensity in the presensce of urea.