Occurrence of plant-uncoupling mitochondrial protein (PUMP) in diverse organs and tissues of several plants

The presence of plant-uncoupling mitochondrial protein (PUMP), previously d escribed by Vercesi et al. (1995), was screened in mitochondria of various organs or tissues of several plant species. This was done functionally, by monitoring purine nucleotide-sensitive linoleic acid-induced uncoupling, or by Western blots. The following findings were established: (1) PUMP was fo und in most of the higher plants tested; (2) since ATP inhibition of linole ic acid-induced membrane potential decrease varied, PUMP content might diff er in different plant tissues, as observed with mitochondria from maize roo ts, maize seeds, spinach leaves, wheat shoots, carrot roots, cauliflower, b roccoli, maize shoots, turnip root, and potato calli. Western blots also in dicated PUMP presence in oat shoots, carnation petals, onion bulbs, red bee t root, green cabbage, and Sedum leaves. (3) PUMP was not detected in mushr ooms. We conclude that PUMP is likely present in the mitochondria of organs and tissues of all higher plants.