Payame Noor University Experimental animal Biology 2322-2387 1 1 2012 10 17 Structural study on pepsin stability in the presence of urea Structural study on pepsin stability in the presence of urea 24 30 131 FA M. Kouhiyan MSc of Biochemistry, payam Noor University B. Shareghi Associated Professor, Shahrekord University F. Kouhiyan MSc of Medical Physic, Isfahan University of Medical Sciences Journal Article 2012 03 13 Pepsin (E.C.3.4.23.1) is a juice gastric aspartic proteinase. It belongs to hydrolyses family. Its monomeris structure is consisting of two lobes that they are similar in size and folding. It consists of a single polypeptide chain of molecular weight 34644 Daltone and 327 aminoacid. Structural analysis shows that pepsin contains 1.2% basic residues, 13.1% acidic residues, 46.5% polar residues and 39.2% hydrophobic residues. Structural stability of pepsin was investigated by UV-VIS spectrophotometer and spectrophlorimetry. Spectral measurements were made by sodium phosphate buffer .02M at pH: 2 and temperatures between 30 and 100 º   C. It was observed that (1) high considerable enzyme stability, (2) enzyme stability decreases in the presence of urea at pH: 2. (3) thermodynamic parameters decline in the presence of urea. (4) Florescence intensity increase in the presence of urea. Pepsin (E.C.3.4.23.1) is a juice gastric aspartic proteinase. It belongs to hydrolyses family. Its monomeris structure is consisting of two lobes that they are similar in size and folding. It consists of a single polypeptide chain of molecular weight 34644 Daltone and 327 aminoacid. Structural analysis shows that pepsin contains 1.2% basic residues, 13.1% acidic residues, 46.5% polar residues and 39.2% hydrophobic residues. Structural stability of pepsin was investigated by UV-VIS spectrophotometer and spectrophlorimetry. Spectral measurements were made by sodium phosphate buffer .02M at pH: 2 and temperatures between 30 and 100 º   C. It was observed that (1) high considerable enzyme stability, (2) enzyme stability decreases in the presence of urea at pH: 2. (3) thermodynamic parameters decline in the presence of urea. (4) Florescence intensity increase in the presence of urea. https://eab.journals.pnu.ac.ir/article_131_624285dfec525655e2072a2dccc18c69.pdf