title: Uptake and processing of the precursor to the small subunit of ribulose 1,5-bisphosphate carboxylase by leucoplasts from the endosperm of developing castor oil seeds.
abstract: Intact leucoplasts from the endosperm of developing castor oil seed were isolated by Percoll density gradient centrifugation. The precursor to the small subunit of ribulose 1,5-bisphosphate carboxylase from pea was synthesized in vitro from hybrid-selected mRNA. Leucoplasts imported this precursor by an ATP-requiring mechanism similar to that described in chloroplasts (AR Grossman et al. 1980 Nature 285: 625-628). The small subunit precursor was processed to a molecular weight that was identical with that of the mature pea small subunit. These results show that leucoplasts, though specialized for fatty acid biosynthesis and not photosynthesis, have a mechanism of protein import similar to that of chloroplasts.
authors: Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
authors: S A
authors: SA
authors: Boyle
authors: S M
authors: SM
authors: Hemmingsen
authors: D T
authors: DT
authors: Dennis