for LDH enzyme assay, after addition of my test sample in the assay reagent, i have recorded decrease in A340nm for approximately 5 mins. i have a data of decrease in OD for 5 mins at interval of 1 min.
how can i calculate ( ΔA340/min test ) ?
Units/ml enzyme= (ΔA340/min test - ΔA340/min blank) *2.7*df / 6.22*0.05
2.7 =total volume of assay
6.22= extinction coefficient of NADH
0.05= volume of sample.
and how to obtain ΔA340/min using the maximum linear rate for both the test and blank?
Hi there,
If you have the data, trace the graph OD=f(t). Normally, you should get a linear decrease. The slope is the velocity of the reaction expressed as variation of OD per time unit.
With the blank the slope should be zero. If not deduce it from your slope data before calculation of activity.
hi Dominique Liger,
for the above problem i have calculated slope for linear decrease. but i am getting slope in negative value.
what should i do? please help
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