Article Title



B Eley


Brendan Eley1 1Washington University School of Medicine, St. Louis, Missouri

Creatine kinase is an enzyme that catalyzes the reversible reaction of phosphocreatine to creatine while yielding ATP from ADP and inorganic phosphate. This mechanism is one of the reasons creatine supplementation is proposed to increase muscular strength. The most studied form of creatine is creatine monohydrate (CrM) although there several other forms. Manufacturers of these different forms of creatine claim to yield better results than the monohydrate form. PURPOSE: The purpose of this study is to determine if creatine kinase activity would be the cause of any difference between creatine forms. METHODS: Creatine kinase activity was measured by a creatine kinase activity colorimetric assay. The forms of creatine used were creatine nitrate (CrN), creatine hydrochloride (CrH), buffered creatine (CrB), and creatine ethyl ester (CrE). Each form of creatine was diluted then solubilized in a reaction mix containing creatine kinase, buffer, adenosine triphosphate, and a color developer. These solutions were pipetted into 8wells each of a 96-well plate. The plate was incubated at 37°C for 30 minutes and read at OD450nm. RESULTS: The OD450mn of the five creatines were CrM = 0.956 ± 0.012, CrN = 0.945 ± 0.045, CrH= 0.912 ± 0.036, CrB = 0.971 ± 0.031, and CrE = 0.951 ± 0.042. One-way ANOVAs were used to determine differences between creatine forms. There was no significant difference in creatine kinase activity between the four forms of creatine compared to the monohydrate(p>0.05). CONCLUSIONS: Creatine kinase activity in the muscle does not seem to be the reason for the increased effectiveness claimed by the various forms. The solution in which the various creatines were dissolved in shows how the creatine kinase would interact with its substrate in an isolated. This may not directly represent the environment of a muscle cell. Future investigation would address if environmental conditions of the cell have any impact on catalyzation of the creatine forms.

ACKNOWLEDGEMENTS: The author claims no external funding sources.

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