Plant Physiol. 1991 Oct;97(2):811-3. doi: 10.1104/pp.97.2.811.

Regulation of sucrose-sucrose-fructosyltransferase in barley leaves.

Plant physiology

D M Obenland, U Simmen, T Boller, A Wiemken

PMID: 16668471 PMCID: PMC1081079 DOI: 10.1104/pp.97.2.811

Abstract

The activity of sucrose-sucrose-fructosyltransferase (SST), a vacuolar enzyme strongly induced by light in excised leaves of barley (Hordeum vulgare L.), rapidly declined even in continuous light upon feeding of cycloheximide (CHI). The rate of decline was similar to that observed in light-treated leaves that were placed into darkness, in the presence or absence of CHI. The protease inhibitor leupeptin totally stopped the decline in SST activity in the dark and caused a substantial increase in the rate of induction of SST activity by light. Feeding of sucrose prevented or even reversed the SST activity decay induced by darkness in the absence of CHI but did not stabilize SST activity in the presence of CHI. The results suggest that SST is continuously subjected to rapid, constant proteolytic degradation in the vacuole, and that the enhancement of SST activity in the light or upon feeding sucrose in the dark is due exclusively to de novo protein synthesis.

References

1. Plant Physiol. 1986 Jun;81(2):444-7 - PubMed
2. Plant Physiol. 1987 Nov;85(3):706-10 - PubMed

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• Journal Article