Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human high molecular weight urokinase, a plasminogen activator, when minimally reduced with 0.01 M 2-mercaptoethanol for 10 h at pH 8.0 and 25 degrees C and then carboxymethylated with sodium iodoacetate, gave two chains, a functionally active heavy chain with about 80% of the original activity and a light chain. These two chains were found to be linked by a single interchain disulfide bond. The functionally active heavy chain can be isolated by an affinity chromatography method with [N alpha-(epsilon-aminocaproyl)-DL-homoarginine hexylester]-Sepharose. The light chain, which has no enzyme activity, is not adsorbed to the affinity matrix, whereas the active heavy chain was adsorbed and subsequently eluted. The active heavy chain was further purified by gel filtration on Sephadex G-100. This preparation was found to be homogeneous by both analytical and sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. The molecular weight of the active heavy chain was determined to be 33,000 by Sephadex G-100 gel filtration and 31,000 by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Its specific activity, with L-pyroglutamyl-glycyl-L-arginine-p-nitroanilide, was determined to be 208,000 IU/mg of protein. Approximately 87% active sites were found by p-nitrophenyl-p'-guanidino-benzoate titration with a molar activity of 7.41 X 10(9) IU/mmol of active site. The active heavy chain when compared to low molecular weight urokinase has a similar molecular weight, specific activity, and amino acid composition. The NH2-terminal residue found in the active heavy chain was lysine which was the same as that found in low molecular weight urokinase, whereas the NH2-terminal residues found in high molecular weight urokinase were serine and lysine. Serine is the NH2-terminal residue of the light chain of high molecular weight urokinase. The steady state kinetic parameters of activation of human Glu-plasminogen by the active heavy chain were also similar to low molecular weight urokinase, as were the amidase parameters of these enzymes. The Michaelis constants of activation (Kplg) were 2.11 and 2.21 microM, respectively; the catalytic rate constants of activation (kplg) were 51.7 and 44.1 min-1, respectively, with second order rate constants, kplg/Kplg of 24.5 and 20.2 microM-1 min-1, respectively.
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PMID:A functionally active heavy chain derived from human high molecular weight urokinase. 634 38

A meta-analysis by the Cochrane Stroke Group (CSG) showed that thrombolytic therapy increased deaths as well as symptomatic and fatal intracranial hemorrhage within the first seven to 10 days and at final follow-up, although these risks are offset by a reduction in disability in survivors, so that there is overall a significant net reduction in the proportion of patients dead or dependent. Trials testing intravenous (i.v.) tPA suggest that it may be associated with less hazard and more benefit. A recent trial demonstrated that intra-arterial pro-urokinase improved long-term outcome in patients with M 1 or M 2 occlusion within 6 hours of onset. Trials of the third generation of thrombolytic agents are ongoing in patients with acute ischemic stroke. The latest CSG's meta-analysis showed that immediate anticoagulant therapy in patients with acute ischemic stroke was not associated with net short or long-term benefit because there was no evidence that anticoagulant therapy reduced deaths or non-fatal stroke during treatment or patients dead or dependent at the end of follow-up. However, an i.v. low-molecular-weight heparinoid showed a trend toward improving long-term outcome in subgroup of patients with atherothrombotic stroke. The thrombin inhibitor argatroban was proven to be comparable to the thromboxane A2 synthetase inhibitor ozagrel in the effect on the outcome at one month in patients with atherothrombotic stroke within 48 hours of onset in Japan, and a trial of the agent is ongoing in patients with ischemic stroke within 12 hours of onset in the United States. Two large trials of aspirin in patients with ischemic stroke within 48 hours of onset indicated that aspirin had a modest effect on reducing patients dead or dependent at the end of follow-up. An international trial of abciximab, a monoclonal antibody directed against platelet glycoprotein IIb/IIIa, is ongoing in patients with ischemic stroke within 6 hours of onset.
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PMID:[Strategy for circulatory disturbance]. 1223 94