Use of purified lyophilized human lactate dehydrogenase isoenzyme 5 in a study of measuring lactate dehydrogenase activity.
We examined the stability of human lactate dehydrogenase (EC 1.1.1.27) isoenzyme 5--purified to a specific activity of about 400 kU/g--when lyophilized in a buffered, stabilized matrix of bovine albumin. This isoenzyme was prepared with a final activity of about 500 U/L and stored at -20, 4, 20, 37, and 56 degrees C for as long as six months. This isoenzyme decayed with approximate first-order kinetics, with an estimated half-life at -20 degrees C of about 475 years. Stability of reconstituted samples stored at 20 or 4 degrees C was poor, suggesting that the reconstituted material should be used without delay; material stored at -20 degrees C showed excellent stability for 15 days. We propose that such preparations might be further investigated as standards for use in electrophoresis of lactate dehydrogenase isoenzymes.
Smith
D A
DA
Department of Clinical Biochemistry, University Hospital, London, Ontario, Canada.
Moses
G C
GC
Henderson
A R
AR
D004795:Enzyme Stability; D005612:Freeze Drying; D006801:Humans; D007525:Isoelectric Focusing; D007527:Isoenzymes; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000032:analysis* / Q000302:isolation & purification*; D012015:Reference Standards
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase