Fraction I Protein

Ellis, R. John

doi:10.1016/b978-0-08-019759-3.50010-9

Cited by 11 publications

(7 citation statements)

References 84 publications

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“…consistent with a molecular weight of 13,000, in good agreement with published values for other sources (8).…”

Section: Studies On the Subunits Of Rudp Carboxylasesupporting

confidence: 79%

“…The enzyme from a number of species has been shown to have a molecular weight of about 550,000 and can be dissociated into two types of subunit (8,18); the larger of about 55,000 MW contains the catalytic site (28) and the smaller of about 13,000 MW which may have a regulatory function (29). Isoelectric focusing (23,36) and peptide mapping (3,21) studies of the subunits from some Nicotiana species have shown that the large subunit is maternally inherited, possibly coded by chloroplast DNA and i~hat the small subunit is inherited in a Mendelian manner characteristic of a nuclear DNA product.…”

Section: I Introductionmentioning

confidence: 99%

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Ribulose 1,5-diphosphate carboxylase from Oenothera. Purification and a peptide mapping procedure for the subunits

Holder

1976

Carlsberg Res. Commun.

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Ribulose 1,5-diphosphate carboxylase has been purified from fully expanded leaves of Oenothera. The isolation procedure overcame the problems which resulted from a high content of mucilage and phenolic compounds in the leaves. Protein extraction into dilute buffer containing a phenol adsorbant and reducing agents followed by a combination of gel filtration and ion exchange chromatography allowed the enzyme to be essentially purified to homogeneity. The purified RuDP carboxylase had a specific activity of 1.5 i.tmoles CO2 fixed, min -~. mg -~ at pH 7.8 and 25 ~ The two subunits could be dissociated in detergent solutions and were found to have molecular weights and amino acid compositions similar to the respective subunits from other sources. A two-dimensional mapping procedure employing ion exchange and paper chromatography was used to partially characterize the tryptic peptides of the RuDP carboxylase subunits; this technique may be useful in interspecific comparisons of the primary structure of the two subunits from Oenothera species.

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“…consistent with a molecular weight of 13,000, in good agreement with published values for other sources (8).…”

Section: Studies On the Subunits Of Rudp Carboxylasesupporting

confidence: 79%

Section: I Introductionmentioning

confidence: 99%

Ribulose 1,5-diphosphate carboxylase from Oenothera. Purification and a peptide mapping procedure for the subunits

Holder

1976

Carlsberg Res. Commun.

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“…Because this enzyme is probably the most abundant protein present in the leaf cell (cf. Ellis, 1973), the scale on which the chloroplast synthesizes its large polypeptide must create a considerable demand for amino acids as necessary precursors. It is conceivable that chloroplasts may be able to import amino acids from elsewhere in the cell in order to sustain protein synthesis.…”

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confidence: 99%

Biosynthesis of Small Molecules in Chloroplasts of Higher Plants

Givan

Harwood

1976

Biological Reviews

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Summary 1. Chloroplasts of higher plants contain enzymes which permit them to synthesize many kinds of small molecules in addition to carbohydrates. 2. Either aqueous or non‐aqueous techniques may be used to isolate chloroplasts. Aqueous methods permit the isolation of chloroplasts showing high rates of photosynthesis; the organelles can be purified by means of density gradients. Non‐aqueously isolated chloroplasts cannot photosynthesize, but show good retention of low‐molecular‐weight substances and soluble enzymes. 3. Whole cells photoassimilating 14CO2 show considerable formation of 14C‐labelled amino acids and lipids, but isolated chloroplasts exhibit very poor synthesis of amino acids and lipids from 14CO2. 4. Chloroplasts play an important rôle in reducing nitrate to ammonia. There is controversy about the presence in chloroplasts of nitrate reductase and about the mechanism of the light‐dependent reduction of nitrate to nitrite; however, it is generally agreed that non‐cyclic electron transport directly supports reduction of nitrite to ammonia via a chloroplastic nitrite reductase. 5. Chloroplasts actively assimilate inorganic nitrogen into amino acids. The assimilation reaction is either the reductive amination of α‐ketoglutarate to glutamate or the ATP‐dependent conversion of glutamate to glutamine. The enzyme glutamate synthase has recently been found to be present in chloroplasts and may play an important function in nitrogen assimilation. 6. Numerous transaminases (aminotransferases) are present in chloroplasts. 7. The source of α‐keto‐acid precursors of chloroplastic amino acids is unknown. It remains to be established whether chloroplasts import the required keto acids or whether some of them might be generated via an incomplete tricarboxylic‐acid cycle located in the chloroplast. 8. Chloroplasts contain characteristically high levels of mono and digalactosyl diglycerides, sulpholipid and phosphatidyl glycerol. They also have large amounts of polyunsaturated fatty acids. 9. Fatty acids are synthesized by the concerted action of fatty‐acid synthetase, elongases and desaturases. Two pathways have been implicated for the formation of α‐linolenic acid. 10. The galactosyldiglycerides are synthesized by successive galactosylation of diglyceride. The enzymes responsible are probably located in the chloroplastic envelope. 11. The other major chloroplastic acyl lipids (sulpholipid, phosphatidylglycerol and phosphatidylcholine) have not been, as yet, synthesized de novo by means of isolated chloroplast fractions. However, indirect evidence indicates that the first two are probably formed there. 12. Chlorophyllide synthesis involves the formation of δ‐aminolaevulinic acid (δALA) followed by conversion of δALA to protoporphyrin IX, which is then transformed into protochlorophyll. 13. Recent evidence favours the view that δALA synthesis is not mediated by δALA synthetase but by another pathway in which δALA can be derived from α‐ketoglutarate or glutamate. It has not been established whether this pathway is loca...

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“…39). In algae and higher plants, this enzyme is localized in the stroma of the chloroplasts (9). The enzyme from eukaryotic species has a molecular weight of about 550,000 and accounts for up to 50 per cent of the total soluble leaf protein (43).…”

Section: Introductionmentioning

confidence: 99%

The cyanogen bromide fragments of the large subunit of ribulosebisphosphate carboxylase from barley

Poulsen

1979

Carlsberg Res. Commun.

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Fraction I Protein

Cited by 11 publications

References 84 publications

Ribulose 1,5-diphosphate carboxylase from Oenothera. Purification and a peptide mapping procedure for the subunits

Ribulose 1,5-diphosphate carboxylase from Oenothera. Purification and a peptide mapping procedure for the subunits

Biosynthesis of Small Molecules in Chloroplasts of Higher Plants

The cyanogen bromide fragments of the large subunit of ribulosebisphosphate carboxylase from barley

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