Adaptive increase of respiratory enzymes in jaundiced patients.

A biochemical analysis of mitochondrial metabolism was made on biopsy specimens of fifteen jaundiced patients. In all but three jaundiced patients the phosphorylative activity based on mitochondrial protein was within normal limits or higher. In nine jaundiced patients the concentrations of cytochrome a(+a3), as representative of respiratory enzymes, increased to more than 1.0 x 10(-10) moles/mg protein, as compared with 0.81 of normal mitochondria, and the relative concentrations of cytochromes, flavoproteins and pyridine nucleotides in relation to cytochrome a(+a3) level remained unchanged. In such patients the phosphorylative activity per unit of cytochrome a(+a3) decreased to approximately 50 per cent of controls, whereas it was within normal limits or greater in jaundiced patients with cytochrome a(+a3) less than 1.0 x 10(-10) moles/mg protein. It is suggested that respiratory enzyme concentrations increase to compensate for the inhibited phosphorylative activity of respiratory assemblies and to maintain the energy balance in the liver in jaundiced patients.