title: Antihypertensive effects of silk fibroin hydrolysate by alcalase and purification of an ACE inhibitory dipeptide.
abstract: Silk fibroin, which is normally discarded as an industrial byproduct in clothing plants, was hydrolyzed with alcalase. Angiotensin I converting enzyme (ACE) inhibitory activities of the silk fibroin hydrolysates (SFH) were investigated, and the hydrolysate with hydrolysis degree of 17% exhibited the highest ACE inhibitory activity. At the tested 600 mg/kg.d and 1200 mg/kg x d doses, SFH significantly lowered blood pressure of spontaneously hypertensive rats (SHR) after chronic oral administration. SFH was further purified using consecutive chromatographic methods on Sephadex G-15 column and reverse phase high-performance liquid chromatography (RP-HPLC) on an octadecylsilane column. After its purity was confirmed by analytical RP-HPLC and capillary electrophoresis, one ACE inhibitory dipeptide was isolated, and its molecular mass and amino acid sequence were determined as 238.2 Da and Gly-Tyr, respectively, by LC-ESI/MS. The results of this study suggest that silk fibroin byproducts have the possibility to become an effective source for ACE inhibitory peptides.
authors.affiliation: School of Agriculture and Bioengineering, Tianjin University, Tianjin 300072, PR China.
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Zhou
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Xue
authors.forename: Jiehua
authors.initials: J
authors.lastname: Wang
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000737:chemistry / Q000302:isolation & purification*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000737:chemistry / Q000302:isolation & purification*; D001407:Bacillus / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry*; D001794:Blood Pressure / Q000187:drug effects; D012831:Bombyx; D004195:Disease Models, Animal; D005349:Fibroins / Q000737:chemistry*; D006801:Humans; D006868:Hydrolysis; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology; D007700:Kinetics; D008297:Male; D011817:Rabbits; D051381:Rats; D011918:Rats, Inbred SHR; D020539:Sequence Analysis, Protein; D013381:Subtilisins / Q000737:chemistry*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D001426:Bacterial Proteins; D005349:Fibroins; D013381:Subtilisins