Fluorescence spectrophotometric studies on the conformational changes induced by omega-aminoacids in two isozymes of Glu-plasminogen (I and II).
Glu-plasminogen I (Glu-plg I: with two carbohydrate chains) and Glu-plg II (with one carbohydrate chain) were separated by a gradient elution of 6 aminohexanoic acid (6AHA) through lysine-Sepharose. Each preparation was excited with ultraviolet light of wave length at 291 nm. The intensity of fluorescence was measured at 340 nm. The intensity of fluorescence increased to a small extent at 0.02 mM of tranexamic acid (t-x) for Glu-plg I and then quickly increased from 0.1 mM of t-x to reach the peak at 0.6 mM. The intensity of fluorescence for Glu-plg II started to increase at 0.2 mM to reach the peak at 0.7 mM. No small increase of fluorescence was observed at less than 0.2 mM of t-x for Glu-plg II. Kdobs of Glu-plg I for t-x and 6AHA were 0.34 mM and 1.35 mM, respectively, whereas Kdobs of Glu-plg II for t-x and 6AHA were 0.46 mM and 3.3 mM, respectively. When Glu-plg I and II were activated by urokinase (UK) and the hydrolysis of S-2251 was measured, the extent of hydrolysis increased in the presence of t-x and 6AHA. The rate of the increase of S-2251 hydrolysis (thus activation rate of Glu-plg I and II with UK) increased in parallel with increase in fluorescence intensity of Glu-plg I and II in the presence of omega-aminoacids. In conclusion, changes in the activation rate with UK and in fluorescence intensity were observed at lower concentrations of omega-aminoacids for Glu-plg I than for Glu-plg II.
D000614:Aminocaproates / Q000494:pharmacology*; D015119:Aminocaproic Acid / Q000494:pharmacology*; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology*; D006801:Humans; D006868:Hydrolysis; D007527:Isoenzymes / Q000032:analysis*; D007700:Kinetics; D010958:Plasminogen / Q000032:analysis*; D011487:Protein Conformation / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D014148:Tranexamic Acid / Q000494:pharmacology*
D000614:Aminocaproates; D003509:Cyclohexanecarboxylic Acids; D007527:Isoenzymes; D014148:Tranexamic Acid; D010958:Plasminogen; D015119:Aminocaproic Acid