title: Studies on the chemical modification of goat liver cystatin and the effect on its anti-papain inhibitory activity.
abstract: Goat liver cystatin was subjected to various chemical modifications in order to ascertain the amino acid residues responsible for its structural and functional integrity. Modification of tryptophan by HNBB led to the complete inactivation of the protein. The inactivation was also accompanied by the complete loss of tryptophan fluorescence at 340 nm. The reaction of liver cystatin with HNBB yielded a characteristic decrease in absorbance at 280 nm. Acetylation of the amino groups of liver cystatin was carried out in the presence of acetic anhydride. The acetylated cystatin showed a decrease in fluorescence intensity at 335 nm which could be attributed to the modification of tyrosine residue due to side reaction.
authors: Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, India.
authors: Aaliya
authors: A
authors: Shah
authors: Mohammad
authors: M
authors: Aatif
authors: Medha
authors: M
authors: Priyadarshini
authors: Mohd Shahnawaz
authors: MS
authors: Khan
authors: Fakhra
authors: F
authors: Amin
authors: Bilqees
authors: B
authors: Bano
mesh_terms: D000042:Absorption; D000089:Acetic Anhydrides / Q000737:chemistry; D000107:Acetylation / Q000187:drug effects; D000818:Animals; D015891:Cystatins / Q000737:chemistry* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006041:Goats; D019791:Guanidine / Q000494:pharmacology; D008099:Liver; D010084:Oxidation-Reduction / Q000187:drug effects; D010206:Papain / Q000037:antagonists & inhibitors*; D011480:Protease Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D014364:Tryptophan / Q000737:chemistry
chemical_list: D000089:Acetic Anhydrides; D015891:Cystatins; D011480:Protease Inhibitors; C031800:acetic anhydride; D014364:Tryptophan; D010206:Papain; D019791:Guanidine