title: Purification and characterization of albumin from frog skin of Duttaphrynus melanostictus.
abstract: Following determination of trypsin inhibitory activity, a serine protease inhibitor was purified and characterized from frog Duttaphrynus melanostictus serum. It was identified as serum albumin, with molecular weight of 67 kDa (DmA-serum). Different from bovine serum albumin, DmA-serum potently inhibited trypsin with similar K(i) values around 1.6 × 10⁻⁷ M. No inhibitory effect on thrombin, chymotrypsin, elastase and subtilisin was observed under the assay conditions. The N-terminal amino acid is EAEPHSRI. Subsequently, a protein with same N-terminal amino acid was purified from skin, termed as DmA-skin. However, DmA-skin is distinct from DmA-serum by binding of a haem b (0.5 mol/mol protein), and with low trypsin inhibitory activity. Frog albumin is distributed in frog skin and exhibited trypsin inhibitory activity, suggesting that it plays important roles in skin physiological functions, like water economy, metabolite exchange and osmoregulation, etc.
authors.affiliation: Key Laboratory of Tropic Biological Resources, Minister of Education, Haikou 570228, China. yingxiazhang@hotmail.com
authors.forename: Ying-Xia
authors.initials: YX
authors.lastname: Zhang
authors.forename: Cong-Wei
authors.initials: CW
authors.lastname: Chen
authors.forename: Manchuriga
authors.initials: M
authors.lastname: Wang
authors.forename: Shuang-Shuang
authors.initials: SS
authors.lastname: Wei
authors.forename: Huai
authors.initials: H
authors.lastname: Guan
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Chi
authors.forename: Xing-Zhu
authors.initials: XZ
authors.lastname: Qi
authors.forename: Wen-Ting
authors.initials: WT
authors.lastname: Hu
mesh_terms: D000818:Animals; D001001:Anura; D005260:Female; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D012709:Serum Albumin / Q000737:chemistry* / Q000302:isolation & purification*; D012867:Skin / Q000737:chemistry*; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D012709:Serum Albumin; D014361:Trypsin Inhibitors