PMID- 7139915
OWN - NLM
STAT- MEDLINE
DCOM- 19830119
LR  - 20190722
IS  - 0009-9147 (Print)
IS  - 0009-9147 (Linking)
VI  - 28
IP  - 12
DP  - 1982 Dec
TI  - Kinetic method having a linear range for substrate concentrations that exceed 
      Michaelis-Menten constants.
PG  - 2359-65
AB  - We describe a new data-processing method for the kinetic quantification of 
      substrates of enzyme-catalyzed reactions. Nonlinear regression is used to fit 
      data for absorbance (A) and rate (dA/dt) vs time to the rate form of the 
      Michaelis-Menten equation. Fitting parameters are the maximum velocity (Vmax), 
      the Michaelis constant (Km), and the total absorbance change (delta A infinity) 
      that would be observed if the reaction were monitored to completion. The method 
      is evaluated with use of the uricase-catalyzed oxidation of uric acid, monitored 
      at 293 nm, as a model reaction. Results for aqueous solutions demonstrate linear 
      calibration plots for concentrations from well below to 3.5-fold the Michaelis 
      constant, a zero temperature coefficient (36-38 degrees C), and near zero 
      dependence on inhibitor (xanthine) concentrations that reduce the initial rate of 
      28% of its uninhibited value. Relative standard deviations (RSDs) vary from about 
      2 to 15%, depending on the data range (95-65% completion) used to process the 
      data. For an 80% reaction data range, the pooled RSD was 6%. The sensitivity for 
      uric acid is 1.15 x 10(4) L mol-1 cm-1 and the detection limit (95% confidence 
      level) is 1.2 x 10(-6) mol/L.
FAU - Hamilton, S D
AU  - Hamilton SD
FAU - Pardue, H L
AU  - Pardue HL
LA  - eng
GR  - GM 13326-15/GM/NIGMS NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Clin Chem
JT  - Clinical chemistry
JID - 9421549
RN  - 0 (Enzymes)
RN  - 268B43MJ25 (Uric Acid)
RN  - EC 1.7.3.3 (Urate Oxidase)
SB  - IM
MH  - *Computers
MH  - Electronic Data Processing
MH  - Enzymes/*metabolism
MH  - Kinetics
MH  - Oxidation-Reduction
MH  - Regression Analysis
MH  - Spectrophotometry, Ultraviolet
MH  - Time Factors
MH  - Urate Oxidase/metabolism
MH  - Uric Acid/analysis/*metabolism
EDAT- 1982/12/01 00:00
MHDA- 1982/12/01 00:01
CRDT- 1982/12/01 00:00
PHST- 1982/12/01 00:00 [pubmed]
PHST- 1982/12/01 00:01 [medline]
PHST- 1982/12/01 00:00 [entrez]
PST - ppublish
SO  - Clin Chem. 1982 Dec;28(12):2359-65.