title: Biochemical and enzymatic properties of a novel marine fibrinolytic enzyme from Urechis unicinctus.
abstract: A novel potent protease, Urechis unicinctus fibrinolytic enzyme (UFE), was first discovered by our laboratory. In this study, we further investigated the enzymatic properties and dynamic parameters of UFE. As a low molecular weight protein, UFE appeared to be very stable to heat and pH. When the temperature was <50 degrees C, the remnant enzyme activity remained almost unchanged, but when the temperature was raised to 60 degrees C the remnant enzyme activity began to decrease rapidly. UFE was quite stable in a pH range of 3.0-12.0, especially at slightly alkaline pH values. Mn(2+), Cu(2+), and Fe(2+) ions were activators of UFE, whereas Fe(3+) and Ag(+) ions were inhibitors. Fe(2+) ion along with Fe(3+) ion might regulate UFE activity in vivo. The optimum pH and temperature of UFE were about 8.0 and 50 degrees C, respectively. When using casein as substrate and a substrate concentration <0.1% casein (w/v), the reaction velocity was increased with substrate concentration. Also when using casein as substrate, the determined K(m) and V(max) of UFE were 0.5298 mg/mL and 3.0845 mol of L-tyrosine equivalent, respectively. Our systematic research results are significant when UFE is applied for medical and industrial purposes.
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao, China. dianliangwang@yahoo.com
authors.forename: Dianliang
authors.initials: D
authors.lastname: Wang
authors.forename: Wanshun
authors.initials: W
authors.lastname: Liu
authors.forename: Baoqin
authors.initials: B
authors.lastname: Han
authors.forename: Ruian
authors.initials: R
authors.lastname: Xu
mesh_terms: D000818:Animals; D000838:Anions / Q000737:chemistry / Q000494:pharmacology; D000845:Annelida / Q000201:enzymology*; D002364:Caseins / Q000378:metabolism; D002412:Cations / Q000737:chemistry / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D005342:Fibrinolysis; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry / Q000494:pharmacology; D007700:Kinetics; D019216:Metals, Heavy / Q000737:chemistry / Q000494:pharmacology; D009792:Oceans and Seas; D010447:Peptide Hydrolases / Q000378:metabolism*; D012834:Silver / Q000737:chemistry / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000838:Anions; D002364:Caseins; D002412:Cations; D019216:Metals, Heavy; D012834:Silver; D007501:Iron; D010447:Peptide Hydrolases