Question

The activity of L-aspartate 4-carboxylase can be assayed by following the evolution of CO2 from L-aspartate: L-aspartate à L-alanine + CO2 . The following results were obtained without an inhibitor and with an inhibitor: Initial velocity (μmol CO2 min-1 ) Concentration of L-aspartate No Inhibitor With Inhibitor (μmol L-1 ) 25 17.0 ---- 33.3 21.3 5.7 50 27.8 8.1 100 41.7 14.7 200 52.6 25.0 i) Calculate the Km and Vmax of the reaction; ii) What type of inhibition is this, justify your answer? iii) Calculate KI for the inhibitor if its concentration is 10 μmol L-1 . (Show your work and show the Lineweaver-Burk plots)

7) The activity of L-aspartate 4-carboxylase can be assayed by following the evolution of CO2 from L-aspartate: L-aspartate -> L-alanine + CO2. The following results were obtained without an inhibitor and with an inhibitor: Initial velocity (umol CO2 min-1) Concentration of L-aspartate No Inhibitor With Inhibitor (umol L-1 25 33.3 50 100 200 17.0 21.3 27.8 41.7 52.6 5.7 8.1 14.7 25.0 i) Calculate the Km and Vmax of the reaction; ii) what type of inhibition is this, justify your answer? iii) Calculate Ki for the inhibitor if its concentration is 10 μmol L-1 . (Show your work and show the Lineweaver-Burk plots)

Answer 1

Conc of L aspartate (umol/L) [S] 1/[S] Initial velocity (umol/min) V without inhibitor 1/V without inhibitor V with inhibitor 1/V with inhibitor 0.04 33.3 0.03003 0.02 0.01 0.005 17 21.3 27.8 41.7 52.6 0.058823529 0.046948357 0.035971223 0.023980815 0.019011407 25 5.7 50 100 200 0.175438596 0.12345679 0.068027211 0.04 14.7 25 1/V vs 1/[S] 0.25 with inhibitor - y 5.4178x+0.0137 0.15 y 1.1414x+0.013 0.05 No inhibitor 0.03 0.01 0.01 0.02 0.03 0.04 0.05 -0.05 0.1 1/[S]

from Te-onphナ (Leith Ae inhibitor) Vmau [s) Slepe Vmox 0.013 @from +- aph-uith-nhǐbh r--一:一5.4112-o013 K.4138 b.013 K, Km 2.101