A comparative study of high molecular weight urokinase and low molecular weight urokinase.
スポンサーリンク
概要
- 論文の詳細を見る
Two forms of urokinase [EC 3. 4. 99. 26] with molecular weights of 51, 600 and 34, 500 were purified from human urine. The specific activities of the high molecular weight urokinase (HMW-UK) and low molecular weight urokinase (LMW-UK) were 157, 400 and 246, 700 International Units (IU/mg), respectively. Purified HMW-UK was 97% active and LMW-UK was 88% active, as judged by using p-nitrophenyl-p'-guanidinobenzoate. LMW-UK had five multiple isoelectric subforms, compared with HMW-UK which had only one. Not only HMW-UK but also LMW-UK was composed of two polypeptide chains linked by disulfide bond (s). The molecular weight of the heavy chain of both forms was the same (34, 000 daltons), while the molecular weight of the light chain of HMW-UK was 17, 600 and that of LMW-UK was approximately 1, 200-3, 400. Enzyme kinetic studies revealed that the kinetic constants, Km and κcat, of both forms toward the synthetic substrates, acetyl-Gly-Lys-methylester (AGLMe) and glutaryl-Gly-Arg-4-methylcoumarin-7-amide (GGA-MCA), were almost the same, but the dissociation constant of HMW-UK toward Glu-plasminogen was 2.4-2.6 times less than that of LMWUK. HMW-UK incubated at 37°C was converted into LMW-UK in an autocatalytic digestion manner leading to no loss of the total activity. These results show that HMW-UK with a higher affinity toward Glu-plasminogen is converted into LMW-UK with a lower affinity, a greater portion of the light chain of HMWUK splitting off.
- 社団法人 日本生化学会の論文
社団法人 日本生化学会 | 論文
- Role of Histidine 46 in the Hydrolysis and the Reverse Transphosphorylation Reaction of RNase Rh from Rhizopus niveus.
- Inhibition of Aspartate Chemotaxis of Escherichia coli by Site-Directed Sulfhydryl Modification of the Receptor.
- Characterization and Primary Structure of a Base Non-Specific and Acid Ribonuclease from Dictyostelium discoideum.
- BIOCHEMICAL STUDIES ON CARBOHYDRATES:XXXV. Chondrosin
- THE INFLUENCE OF INORGANIC IONS ON THE ACTIVITY OF AMYLASES