Release of cryptic monoamine oxidase activity by growth of BHK-21 cells in D-chloramphenicol

The activity of monoamine oxidase, a marker enzyme of the outer mitochondrial membrane, is stimulated in BHK cells grown in the presence of 100 microgram ml-1 D-chloramphenicol. The observed stimulation can be reversed by removal of the antibiotic. Addition of the non-ionic detergent Triton X-100, to cell homogenates results in an elevation of the enzyme activity similar to that produced by D-chloramphenicol treatment. The activation by chloramphenicol is apparently related to a release of cryptic monoamine oxidase activity.