Cysteine Synthase from Rape Leaves

Morimoto, Masahiro; Fukushima, Kazuo; Tamura, Goro

doi:10.1093/oxfordjournals.jbchem.a130811

Cited by 44 publications

(20 citation statements)

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“…The necessity for a broad ammonium sulfate cut to precipitate most of the OASS activities from both legume species studied is in accord with results reported for enzyme preparations from spinach leaves (7), mature rape leaves (14), kidney bean seedlings (22), and mature radish roots (23). The ammonium sulfate step also indicated some variability in the tolerance of the enzymes to ammonium sulfate, with preparations from P. vulgaris losing 39% of their activity when the ammonium sulfate saturation was increased from 40 to 90% while preparations from P. polyanthus lost only 6% of their activity.…”

Section: Methodssupporting

confidence: 84%

“…Activity of the multienzyme complex of OASS with serine transacetylase was assayed at 25 C by the sulfide ion electrode assay method (5) (Table II) and 4,600 units from 45 g of P. polyanthus (Table III). These values are about an order of magnitude greater than enzyme preparations from mature rape leaves (14) or radish roots (23) and several orders of magnitude larger than that obtained from kidney bean seedlings (22). It should be noted that the investigations on the mature rape leaves, radish roots, and kidney bean seedlings employed a Kphosphate buffer (pH 8) for the grinding medium and homogenization of the tissues in a Waring Blendor.…”

Section: Methodsmentioning

confidence: 92%

“…Preparations of OASS from kidney bean seedlings (20) as well as mature rape leaves (14) have been reported to be soluble rather than particulate. This appears to be the case in the present study as well, since centrifugation of the crude homogenate at 100,000g for 50 min sediments less than 1% of the total activity.…”

Section: Methodsmentioning

confidence: 99%

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Purification and Initial Kinetic Characterization of Different Forms of O-Acetylserine Sulfhydrylase from Seedlings of Two Species of Phaseolus

Bertagnolli

Wedding²

1977

Plant Physiol.

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Purification of 0-acetylserine sulfuydrylase (OASS) from seedlings of two species of Phaseolus reveals the presence in both species of two forms of this enzyme. The isolation and purification procedure gives purification of 7-to 160-fold for individal isoenzymes with specific activities ranging from 33 IU mg-' to 775 IU mg-' protein.Detailed study of the basic kinetic parameters of the OASS isoenzymes indicates that both forms from Phaseolus vulgaris (which are of about equal specific activity) display substrate inhibition by S2-above 1 mm and positive cooperativity at lower concentrations of S2-. With respect to 0-acetylserine (OAS), the second substrate of the reaction, one P. vulgaris isoenzyme shows substrate inhibition by OAS concentrations above 10 mM, while the second is unaffected by OAS concentrations up to 50 mm. The isoenzymes from Phaseolus polyanthus (one of which has a specific activity 24 times higber than the other) are sligtly and approximately equally inhibited by both S2-and OAS.There is increasing evidence that a variety of plants including spinach (6), kidney bean (20,22), and species of rape, snapdragon, sunflower, wheat, barley, carrot, aster, flax, and pumpkin (18) synthesize cysteine by a two-step process similar to that known to occur in bacteria (12). First, OAS' is formed in a reaction catalyzed by serine transacetylase. Then, cysteine is synthesized from OAS and sulfide by OASS (15,(20)(21)(22)(23). Unlike bacteria, there is no evidence for the existence of a multifunctional protein complex of serine transacetylase-OASS in higher plants (20,22).This report is concerned with comparison of some of the properties of OASS from 5-day etiolated seedlings of Phaseolus vulgaris and Phaseolus polyanthus. These species were chosen because the amount of cysteine in seed proteins of P. polyanthus was approximately three times that of P. vulgaris (2). A relatively simple method of isolation which gives a good yield of the enzymes and which leads to purification to homogeneity as judged by disc gel electrophoresis has been developed. These studies indicate the existence of two isoenzymes of OASS from each species of legume investigated.

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Section: Methodssupporting

confidence: 84%

Section: Methodsmentioning

confidence: 92%

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Purification and Initial Kinetic Characterization of Different Forms of O-Acetylserine Sulfhydrylase from Seedlings of Two Species of Phaseolus

Bertagnolli

Wedding²

1977

Plant Physiol.

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“…In wheat and rape leaves and kidney bean seedlings, the enzyme is apparently cytoplasmic (3,14,16) whereas in spinach, white clover, and pea leaves the enzyme is associated with chloroplasts (7,15). A recent report suggests that cystathionine ,-lyase (EC 4.4.1.8) in barley leaves is at least partially chloroplastic (17).…”

mentioning

confidence: 99%

Sulfate Assimilation in C₄ Plants

Burnell¹

1984

Plant Physiol.

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The activity of ATP sulfurylase, cysteine synthase, and cystathionine jl-lyase was measured in crude leaf extracts, bundle sheath strands, and mesophyll and bundle sheath chloroplasts to determine the location of sulfate assimilation of C4 plant leaves. Almost all the ATP sulfurylase activity was located in the bundle sheath chloroplasts while cysteine synthase and cystathionine j-lyase activity was located, in different proportions, in both chloroplast types.A new spectrophotometric assay for measuring ATP sulfurylase activity is also described.The C4 pathway of CO2 assimilation is compartmentalized into specific cell types with atmospheric CO2 initially being fixed into organic acids in the Although it is generally agreed that in C3 plants, chloroplasts are the main site of S42-assimilation (activation and reduction to S2-) (1) the subcellular distribution of cysteine synthase (EC 4.2.99.8) appears to differ between plant species. In wheat and rape leaves and kidney bean seedlings, the enzyme is apparently cytoplasmic (3,14,16) whereas in spinach, white clover, and pea leaves the enzyme is associated with chloroplasts (7, 15). A recent report suggests that cystathionine ,-lyase (EC 4.4.1.8) in barley leaves is at least partially chloroplastic (17). This paper reports on the inter-and intracellular location of ATP sulfurylase, cysteine synthase and cystathionine ,B-lyase in Zea mays. A new spectrophotometric assay for ATP sulfurylase is also described.

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“…D) Recently cysteine synthase [O-acetyl-L-serine acetatelyase (adding hydrogen-sulfide) EC 4.2.99.8) has been prepared to a highly purified state from rape leaves and extensively characterized. 9 ) Apart from this leaf cysteine synthase, we wish to report the isolation and characterization of that enzyme from non-green tissue. Cysteine synthase from mature roots of radish (Raphanus sativas L.) was purified 280-fold by the procedures, similar to that previously described for leaf enzyme,9) heat treatment and ammonium sulfate fractionation followed by chromatography on DEAE-Sephadex A-50 and Sephadex G-100.…”

mentioning

confidence: 99%