Creatine kinase response surfaces explored by use of factorial experiments and simplex maximization.

1983 ◽  
Vol 29 (5) ◽  
pp. 793-799 ◽  
Author(s):  
D M Fast ◽  
E J Sampson ◽  
V S Whitner ◽  
M Ali
Keyword(s):  
Creatine Kinase ◽  
Response Surface ◽  
Kinase Activity ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Creatine Kinase Activity ◽  
Response Surfaces ◽  
Optimal Conditions ◽  
Reaction Conditions ◽  
Sensitivity Reaction

Abstract We conducted a five-component, five-level response-surface experiment to optimize the pH and the concentrations of magnesium, creatine phosphate, adenosine diphosphate, and buffer in an assay for creatine kinase. Under optimal conditions, creatine kinase activity was about 5% greater than that obtained with a previously reported assay (Clin Chem 23: 1569, 1977). We also applied a simplex maximization algorithm to the response-surface equation to locate areas of maximum sensitivity. Reaction conditions for two such areas were found, each yielding approximately 11% more activity than with the previously reported method.

Multivariate examination of response surfaces around the reaction conditions for the Scandinavian Society's recommended method for creatine kinase determinations.

1984 ◽  
Vol 30 (8) ◽  
pp. 1322-1326 ◽  
Author(s):  
E J Sampson ◽  
V S Whitner ◽  
M Ali ◽  
D M Fast
Keyword(s):  
Creatine Kinase ◽  
Kinase Activity ◽  
Polynomial Equation ◽  
Creatine Phosphate ◽  
Creatine Kinase Activity ◽  
Response Surfaces ◽  
Least Squares Regression ◽  
Reaction Conditions ◽  
Surface Data ◽  
Reaction Surfaces

Abstract We examined the reaction surfaces around five variables (imidazole, ADP, creatine phosphate, magnesium, and pH) in the Scandinavian method for determining creatine kinase, using factorial experimentation (five level, five factor) at reaction temperatures of 30 and 37 degrees C. Theoretical response surfaces were computed by fitting a quadratic polynomial equation to the experimental data by least-squares regression. Essentially no differences were apparent in the theoretical curves among the five specimens we analyzed, or between reaction temperatures. Our response-surface data showed the following: for pH and imidazole, activity optima in the region of the Scandinavian conditions; for creatine phosphate, a broad plateau over the concentration range investigated (10 to 50 mmol/L); and for magnesium and ADP, gently increasing contours with maximal creatine kinase activity at concentrations greater than those investigated in our study (magnesium 15 mmol/L, ADP 3.5 mmol/L).

Automated Method for the Determination of Serum Creatine Kinase Activity

1967 ◽  
Vol 13 (3) ◽  
pp. 233-241 ◽  
Author(s):  
Gerard A Fleisher
Keyword(s):  
Creatine Kinase ◽  
Alkaline Solution ◽  
Kinase Activity ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Creatine Kinase Activity ◽  
Serum Creatine Kinase ◽  
Colorimetric Determination ◽  
Automated Method

Abstract An automated (AutoAnalyzer) method for the colorimetric determination of creatine kinase activity in serum is described. This method includes reactivation of creatine kinase with cysteine, incubation of the active enzyme with creatine phosphate and adenosine diphosphate at 37.5°, and subsequent inactivation of enzyme and binding of cysteine by phenylmercuric borate. The enzymatically produced creatine is dialyzed against a solution of diacetyl and reacted with α-naphthol in an alkaline solution. The absorbance of the colored end product is measured at 550 mµ. Individual blanks are determined in the absence of adenosine diphosphate. Comparison of results obtained by this method and a manual procedure shows satisfactory agreement.

Evaluation of a New Procedure for Measuring Serum Creatine Kinase Activity

1970 ◽  
Vol 16 (5) ◽  
pp. 370-374 ◽  
Author(s):  
J Henry Wilkinson ◽  
B Steciw
Keyword(s):  
Creatine Kinase ◽  
Spectrophotometric Method ◽  
Kinase Activity ◽  
Creatine Phosphate ◽  
Sample Volume ◽  
Creatine Kinase Activity ◽  
Serum Creatine Kinase ◽  
Normal Range ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract A new spectrophotometric microtechnique for the determination of serum creatine kinase activity, in which all reagents are provided in a single com-pressed tablet, has been evaluated. The procedure depends upon coupling the creatine phosphate-ADP reaction with the hexokinase and glucose-6-phosphate dehydrogenase reactions. The new technique is quick, relatively simple, and gives results which compare favorably with the conventional spectrophotometric method in precision and sensitivity. It requires a sample volume of 10 Al, and values ranging from 10 to1600 U/liter can be determined without dilution. Gross hemolysis leads to erroneously high values, but the error is negligible with slightly hemolyzed specimens. A provisional normal range has been established

Perinatal enhancement of cardiac myofibrillar creatine kinase activity without change in enzyme Km

1993 ◽  
Vol 265 (2) ◽  
pp. C375-C378 ◽  
Author(s):  
R. T. Dowell ◽  
M. C. Fu
Keyword(s):  
Creatine Kinase ◽  
Heart Development ◽  
Kinase Activity ◽  
Creatine Phosphate ◽  
Creatine Kinase Activity ◽  
Site Function ◽  
A Subunit ◽  
Michaelis Constants ◽  
Isoenzyme Composition ◽  
Contractile Performance

Myofibrillar creatine kinase (CK) serves as one microcompartment of the phosphorylcreatine shuttle by providing ATP as substrate for adenosinetriphosphatase (ATPase). During perinatal heart development, augmentations of myofibrillar ATPase and CK occur in concert with increased contractile performance. The maximal reaction velocity (Vmax) for CK doubles during development in both intact native myofibril and enzyme extracted from myofibril. The absence of alterations in ADP and creatine phosphate substrate Michaelis constants (Km), isoenzyme composition, or total number of -SH groups suggests active site function (Vmax) is influenced indirectly via a subunit domain effect on enzyme conformation.

scholarly journals Adenosine Diphosphate Requirement in the Creatine Phosphate-Induced Contraction of the Glycerinated Rabbit Psoas

1962 ◽  
Vol 46 (2) ◽  
pp. 215-223 ◽  
Author(s):  
William D. Cohen ◽  
Jeanne Schneebaum ◽  
Teru Hayashi
Keyword(s):  
Creatine Kinase ◽  
Contractile Activity ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Creatine Kinase Activity ◽  
Tension Development ◽  
Rabbit Psoas ◽  
Free Nucleotide ◽  
Glycerinated Fibers ◽  
Dowex 1

Glycerinated rabbit psoas fibers were tested for their ability to contract under the influence of creatine phosphate and creatine kinase in the absence of free nucleotide. Tension development by the fibers was observed upon addition of creatine phosphate to the medium containing creatine kinase purified to the first lyophilization stage. However, when the enzyme was washed free of nucleotides by treatment with the anion exchange resin Dowex 1, no contraction occurred until free nucleotide was supplied. In all experiments, contractile activity of the psoas fibers was the criterion for determining the enzyme activity concerned. Using this criterion, creatine kinase activity native to the glycerinated fibers was also demonstrated. No evidence for direct transphosphorylation of the bound nucleotide of the fiber was found.

Influence of peroxynitrite on energy metabolism and cardiac function in a rat ischemia-reperfusion model

2003 ◽  
Vol 285 (4) ◽  
pp. H1385-H1395 ◽  
Author(s):  
Warren H. Lee ◽  
John S. Gounarides ◽  
Eric S. Roos ◽  
Michael S. Wolin
Keyword(s):  
Creatine Kinase ◽  
Kinase Activity ◽  
Ischemia Reperfusion ◽  
Creatine Phosphate ◽  
High Energy ◽  
Left Ventricular ◽  
Creatine Kinase Activity ◽  
Rate Pressure Product ◽  
Partial Recovery ◽  
Developed Pressure

Ischemia-reperfusion generates peroxynitrite (ONOO–), which interacts with many of the systems altered by ischemia-reperfusion. This study examines the influence of endogenously produced ONOO– on cardiac metabolism and function. Nitro-l-arginine (an inhibitor of ONOO– biosynthesis) and urate (a scavenger of ONOO–) were utilized to investigate potential pathophysiological roles for ONOO– in a rat Langendorff heart model perfused with glucose-containing saline at constant pressure and exposed to 30 min of ischemia followed by 60 min of reperfusion. In this model, ischemia-reperfusion decreased contractile function (e.g., left ventricular developed pressure), cardiac work (rate-pressure product), efficiency of O2 utilization, membrane-bound creatine kinase activity, and NMR-detectable ATP and creatine phosphate without significantly altering the recovery of coronary flow, heart rate, lactate release, and muscle pH. Treatment with urate and nitro-l-arginine produced a substantial recovery of left ventricular developed pressure, rate-pressure product, efficiency of O2 utilization, creatine kinase activity, and NMR-detectable creatine phosphate and a partial recovery of ATP. The pattern of effects observed in this study and in previously published work with similar models suggests that ONOO– may alter key steps in the efficiency of mitochondrial high-energy phosphate generation.

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