Isolation of transketolase from rabbit liver and comparison of some of its kinetic properties with transketolase from other sources.
1. Rabbit liver transketolase activity was purified 56-fold using the following steps: ammonium sulfate precipitation, chromatography on DEAE-Sephadex A-25, concentration through an Amicon ultrafiltration cell and rechromatography on DEAE-Sephadex A-25. 2. The enzyme showed an optimum PH for activity at 7.8-8.0. 3. The optimum temperature was around 40 degrees C and the activation energy calculated from the Arrhenius plot was found to be 11.4 kcal/mole. 4. The molecular weight of the enzyme, as determined by gel filtration, was found to be approximately 162,000, while the content of thiamin diphosphate was between 1.8 and 2 mumole per mole protein. 5. Addition of thiamin diphosphate and magnesium chloride did not influence the activity. 6. From the kinetic studies of the enzyme, the Km values for xylulose-5-phosphate, ribose-5-phosphate and fructose-6-phosphate were 3.8 x 10(-5) M, 9.5 x 10(-5) M and 1.1 x 10(-2) M, respectively.
Masri
S W
SW
Department of Biochemistry, Faculty of Science, University of Kuwait, Safat.
Ali
M
M
Gubler
C J
CJ
D000818:Animals; D002852:Chromatography, Ion Exchange; D005260:Female; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D011817:Rabbits; D013045:Species Specificity; D013816:Thermodynamics; D014174:Transketolase / Q000302:isolation & purification / Q000378:metabolism*
D014174:Transketolase