New methods for the study of complex enzyme kinetics illustrated by analysis of the wavy curves of v versus (S) and non-linear double-reciprocal plots for human-placental 15-hydroxyprostaglandin dehydrogenase.
A new method for discovering the minimum degree of rate equations using only the experimental graphs and a straight-edge (transparent ruler) is presented. This method is then illustrated by an analysis of the wavy v vs [S] curves and non-linear double-reciprocal plots reproducibly given by NAD-dependent 15-hydroxyprostaglandin dehydrogenase for which a new improved purification is described. It is shown by this analysis that the enzyme has a complex mechanism involving cooperatively linked dependent sites and requiring a rate equation of at least fourth degree in prostaglandin and NAD+ with no kinetically significant dead-end complexes.
D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D005260:Female; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000378:metabolism*; D007700:Kinetics; D008433:Mathematics; D008722:Methods; D009243:NAD; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy
D009243:NAD; D000429:Alcohol Oxidoreductases; D006911:Hydroxyprostaglandin Dehydrogenases