The Occurrence of the Protochlorophyllide Reductase From Oat Etioplasts as a Single 37 kD Polypeptide

Röper, Ursula; Bergweiler, Paul

doi:10.1016/s0044-328x(83)80065-8

Cited by 8 publications

(2 citation statements)

References 17 publications

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“…For In previous studies of angiosperms, more than one immunoreactive polypeptide has occasionally been seen that crossreacted with an antiserum raised against the purified POR. In most cases, however, these polypeptides have not been attributed to a POR-related protein but to secondary modifications of the light-sensitive POR enzyme during its isolation (26). In the present work, we have reinvestigated the presence of additional POR-related polypeptides in barley by analyzing leaf proteins under conditions that should minimize artificial modifications of the POR enzyme.…”

Section: Methodsmentioning

confidence: 99%

Two routes of chlorophyllide synthesis that are differentially regulated by light in barley (Hordeum vulgare L.).

Holtorf

Reinbothe

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

197

201

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NADPH-protochlorophyllide oxidoreductase (POR; EC 1.6.99.1) catalyzes the only known light-dependent step in chlorophyll synthesis of higher plants, the reduction of protochlorophyllide (Pchlide) to chlorophyllide. In barley, two distinct immunoreactive POR proteins were identified. In contrast to the light-sensitive POR enzyme studied thus far (POR-A), levels of the second POR protein remained constant in seedlings during the transition from dark growth to the light and in green plants. The existence of a second POR-related protein was verified by isolating and sequencing cDNAs that encode a second POR polypeptide (POR-B) with an amino acid sequence identity of 75% to the POR-A. In the presence of NADPH and Pchlide, the in vitro-synthesized POR-A and POR-B proteins could be reconstituted to ternary enzymatically active complexes that reduced Pchlide to chlorophyllide only after illumination. Even though the in vitro activities of the two enzymes were similar, the expression of their genes during the light-induced transformation of etiolated to green seedlings was distinct. While the POR-A mRNA rapidly declined during illumination of dark-grown seedlings and soon disappeared, POR-B mRNA remained at an approximately constant level in dark-grown and green seedlings. Thus these results suggest that chlorophyll synthesis is controlled by two light-dependent POR enzymes, one that is active only transiently in etiolated seedlings at the beginning of illumination and the other that also operates in green plants.

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Section: Methodsmentioning

confidence: 99%

Two routes of chlorophyllide synthesis that are differentially regulated by light in barley (Hordeum vulgare L.).

Holtorf

Reinbothe

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

197

201

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“…The enzyme has a molecular mass of 36 to 37 kD (Apel et al, 1980;Beer and Griffiths, 1981;Roper et al, 1983;Forreiter et al, 1990) and is one of the major proteins localized in the prolamellar body of etioplasts (Griffiths, 1978;Dehesh et al, 1986;Ryberg and Dehesh, 1986). Small amounts of the enzyme have also been reported to be localized in thylakoid membranes (Forreiter and Apel, 1993;Teakle and Griffiths, 1993) or envelopes (Joyard et al, 1990;Pineau et al, 1993) of mature chloroplasts.…”

mentioning

confidence: 99%

Correlated Changes in the Activity, Amount of Protein, and Abundance of Transcript of NADPH:Protochlorophyllide Oxidoreductase and Chlorophyll Accumulation during Greening of Cucumber Cotyledons

et al. 1995

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Changes in the activity and abundance of NADPH:protochlorophyllide oxidoreductase (NPR) and the abundance of mRNA encoding it were examined during the greening of 5-d-old etiolated cucumber cotyledons under continuous illumination. To measure NPR activity in the extracts from fully greened tissues, we have developed an improved method of assay. Upon exposure of etiolated cotyledons to light, NPR activity decreased rapidly within the first 2 h of exposure. Thereafter, enzymatic activity increased transiently, reaching a submaximum level at 12 h, and decreased slowly. The level of immunodetectable NPR protein followed the same pattern of changes during 96 h of greening as observed for NPR activity. The NPR mRNA in etiolated cotyledons disappeared quickly in the 1st h of irradiation. However, the level of mRNA increased thereafter to reach 3-fold or more of the dark level at 12 h and then decreased. The changes in the activity, protein level, and mRNA level after the first rapid decreases corresponded chronologically and nearly paralleled the increase in the rate of chlorophyll accumulation. These findings suggest that the greening of cucumber cotyledons is regulated basically by the level of NPR protein without activation or repression of enzymatic activity and that NPR mRNA increased by light maintains the level of enzyme protein necessary for greening.

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Proteolytic Effects on the Protochlorophyllide-Oxidoreductase in Oat

Röper

1984

Protochlorophyllide Reduction and Greening

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The Occurrence of the Protochlorophyllide Reductase From Oat Etioplasts as a Single 37 kD Polypeptide

Cited by 8 publications

References 17 publications

Two routes of chlorophyllide synthesis that are differentially regulated by light in barley (Hordeum vulgare L.).

Two routes of chlorophyllide synthesis that are differentially regulated by light in barley (Hordeum vulgare L.).

Correlated Changes in the Activity, Amount of Protein, and Abundance of Transcript of NADPH:Protochlorophyllide Oxidoreductase and Chlorophyll Accumulation during Greening of Cucumber Cotyledons

Proteolytic Effects on the Protochlorophyllide-Oxidoreductase in Oat

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