(1) Malic Acid is the only metabolite of the Krebs Cycle which falls in concentration during exhaustive physical activity.(2) Homocysteine is an intermediary metabolite of essential dietary amino acid methionine.(3) The plasma membrane transport of other metabolites such as amino acids and sugars can also be assayed by the changes in membrane potential.(4) All of these require metabolism to form genotoxic metabolites in vivo.(5) In other reviews, the role of nitrate and nitrogen metabolites in regulating metabolism and development has been discussed.
