Key Laboratory of Tropic Biological Resources

Haikou, China

Key Laboratory of Tropic Biological Resources

Haikou, China
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Zhang Y.,Key Laboratory of Tropic Biological Resources | Zhang Y.,Hainan Key Laboratory of Tropical Hydrobiology Technology | Zhang Y.,Hainan University | Wang M.,Hainan University | Wei S.,Hainan University
Toxicon | Year: 2010

Amphibian skin secretions contain many bioactive compounds. A trypsin inhibitor termed KPHTI was purified from the skin secretions of frog Kaloula pulchra hainana by successive ion-exchange and gel-filtration chromatography. KPHTI is a single chain glycoprotein, with an apparent molecular weight of 23 kDa in SDS-PAGE. It is a competitive inhibitor and effectively inhibits trypsin catalytic activity on peptide substrate with the inhibitor constant (K i) value of 27 nM. KPHTI shows no inhibitory effect on chymotrypsin, thrombin, elastase, and subtilisin. The N-terminal sequence of KPHTI is DHEVTS, which shows no similarity with other known trypsin inhibitors. DTT apparently affected the inhibitory activity of KPHTI. But it was not sensitive to temperature and pH range, which suggested that it possessed stable trypsin inhibitory activity in natural environment, and maybe play an important role in against predators. © 2010 Elsevier Ltd.


Zhang Y.-X.,Key Laboratory of Tropic Biological Resources | Zhang Y.-X.,Hainan University | Chen C.-W.,Key Laboratory of Tropic Biological Resources | Chen C.-W.,Hainan University | And 9 more authors.
Protein Journal | Year: 2011

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. © 2011 Springer Science+Business Media, LLC.


Yuan W.,CAS Fujian Institute of Research on the Structure of Matter | Yuan W.,Key Laboratory of Tropic Biological Resources | Liu T.,CAS Fujian Institute of Research on the Structure of Matter | Guo Z.,CAS Fujian Institute of Research on the Structure of Matter | And 2 more authors.
Journal of Molecular Structure | Year: 2010

Two cadmium(II) coordination polymers, [Cd6(L1)4(H2O)11]n·4nH2O (1) and [Cd(L2)(H2O)]n·2nH2O (2), were synthesized under different pH from two multi-carboxylate ligands, N-(3-carboxyphenyl)iminodiacetic acid (H3L1) and 5-aminoisophthalic acid (H2L2), respectively. Complex 1 has a 2D layer structure, which is generated through 1D zigzag Cd...Cd chains with coexisting left-handed and right-handed helices connected together by (L1)3-. Complex 2 consists of a 2D (3, 6)-connected (4,3 6) net. At room temperature, complex 1 exhibits a strong emission at 442 nm upon excitation at 350 nm, and complex 2 exhibits an intense emission with double peaks at 384 and 400 nm upon excitation at 355 nm. © 2009 Elsevier B.V. All rights reserved.


PubMed | Key Laboratory of Tropic Biological Resources
Type: Journal Article | Journal: The protein journal | Year: 2011

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 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.

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