Citrate cleavage enzyme in mango fruit

Mattoo, Autar K.; Modi, V. V.

doi:10.1016/0006-291x(70)90408-0

Cited by 39 publications

(32 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus the mammalian enzyme is stabilized by adding glycerol and citrate and storing in the frozen state (7), it is strongly inhibited by (-)- hydroxycitrate and the mol wt of one form of the enzyme (ACL I) is about 400,000 (17). The pH optimum for the castor bean ACL is 7.5, somewhat lower than that from chicken and rat liver (12), but close to the optimum pH 7 for the enzyme from mango fruit (6). In animal tissues the enzyme is cytosolic (16,17) and generates acetyl-CoA used by the soluble fatty acid synthetase.…”

Section: Resultsmentioning

confidence: 93%

ATP Citrate Lyase from Germinating Castor Bean Endosperm

Fritsch¹,

Beevers²

1979

Plant Physiol.

View full text Add to dashboard Cite

ATP citrate lyase (EC 4.1.3.8) This enzyme was first described by Srere and Lipmann (18) in pigeon liver and has been further characterized in chicken and rat liver (17). It is widely distributed in animal tissues and shows high activity in liver, adipose tissue, lactating mammary glands, brain and adrenal tissue (7,16,17). ACL was found to be localized in the cytosol (16). (-)-Hydroxycitrate has been shown to be a potent and specific competitive inhibitor of the enzyme (17). In animals, particularly those on a high carbohydrate diet, ACL plays an important role in fatty acid synthesis (17). Citrate generated in the mitochondria is cleaved by ACL in the cytosol, providing the acetyl-CoA used there in fatty acid biogenesis. Accordingly, exogenous citrate is a good precursor of fatty acids and (-)-hydroxycitrate is an inhibitor of fatty acid synthesis from suitable precursors in vivo (17 MATERIALS AND METHODS Castor bean seeds (Ricinus communis cv. Hale) were soaked overnight in running tap water, sown in water-saturated Vermiculite, and grown at 30 C in darkness. Endosperms were removed from seedlings, rinsed in ice cold water, and kept on ice until homogenization.Crude extracts were prepared by grinding the endosperms from five seedlings in 5 ml 0.1 M Tricine-KOH (pH 7.5) containing 10 mm mercaptoethanol and 0.1% Triton X-100 in a chilled mortar. The resulting slurry was centrifuged at 30,000g for 20 min in a refrigerated centrifuge. The fat layer and pellet were discarded and the supernatant solutions used as the crude extract. Extracts of endosperm from ripening castor bean at the stage when the testae were just beginning to color were prepared in the same way. Seeds of watermelon (Citrullus vulgaris), sweet corn (Zea mays), soybean (Glycine max), sunflower (Helianthus annuus), peanut (Arachis hypogea), and mung bean (Phaseolus aureus) were germinated as for castor beans. For the preparation of crude extracts, the roots and lower half of the hypocotyl were removed and the rest of the seedling homogenized and centrifuged as described above. From sweet corn the coleoptile (including the primary leaf) and scutellum were extracted. In preparing castor bean extract for the time course studies some sand was added to facilitate grinding.Total citrate in the endosperm tissue was extracted in dilute HClO4 and estimated using the malate dehydrogenase coupled assay with commercial bacterial citrate lyase (2). Protein concentrations were determined by the biuret reaction or a modified Lowry procedure (3).For the preparation of organelles, 20 isolated endosperms were chopped with razor blades in 14 ml 0.15 M Tricine-KOH (pH 7.5) containing 10 mm 2-mercaptoethanol, I mm EDTA, and 20o sucrose (w/w). The homogenate was passed through three layers of nylon cloth and 10 ml of the filtrate was layered on top of a linear sucrose gradient. The gradient consisted of 40 ml 30 to 60%o sucrose containing 10 mm citrate and 1 mm EDTA, over a cushion of 62% sucrose, and topped by 4 ml 30%o sucrose containing the same additives...

show abstract

Section: Resultsmentioning

confidence: 93%

ATP Citrate Lyase from Germinating Castor Bean Endosperm

Fritsch¹,

Beevers²

1979

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…The occurrence of ACL in plants was suggested over 30 years ago by the detection of its enzymatic activity in plant extracts (Mattoo and Modi, 1970;Rinne, 1975, 1977). More recently, EST cDNA clones that share sequence similarity with the animal ACL have further supported this supposition (Wurtele et al, 1998;Suh et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Several possible mechanisms for generating acetyl-CoA in the plastid for fatty acid biosynthesis have been described. However, the relative significance of each of these mechanisms is not yet clear (Mattoo and Modi, 1970;Elias and Givan, 1979;Liedvogel and Stumpf, 1982;Givan, 1983;Kaethner and ap Rees, 1985;Randall et al, 1989;Wurtele et al, 1998;Bao et al, 2000;Ke et al, 2000a). Recent studies indicate that the acetyl-CoA pool required for de novo fatty acid biosynthesis is primarily generated by the plastidic isoform of the pyruvate dehydrogenase complex (Ke et al, 2000a).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Molecular Characterization of a Heteromeric ATP-Citrate Lyase That Generates Cytosolic Acetyl-Coenzyme A in Arabidopsis,

Fatland¹,

Ke²,

Anderson³

et al. 2002

Plant Physiology

194

View full text Add to dashboard Cite

Acetyl-coenzyme A (CoA) is used in the cytosol of plant cells for the synthesis of a diverse set of phytochemicals including waxes, isoprenoids, stilbenes, and flavonoids. The source of cytosolic acetyl-CoA is unclear. We identified two Arabidopsis cDNAs that encode proteins similar to the amino and carboxy portions of human ATP-citrate lyase (ACL). Coexpression of these cDNAs in yeast (Saccharomyces cerevisiae) confers ACL activity, indicating that both the Arabidopsis genes are required for ACL activity. Arabidopsis ACL is a heteromeric enzyme composed of two distinct subunits, ACLA (45 kD) and ACLB (65 kD). The holoprotein has a molecular mass of 500 kD, which corresponds to a heterooctomer with an A 4 B 4 configuration. ACL activity and the ACLA and ACLB polypeptides are located in the cytosol, consistent with the lack of targeting peptides in the ACLA and ACLB sequences. In the Arabidopsis genome, three genes encode for the ACLA subunit (ACLA-1, At1g10670; ACLA-2, At1g60810; and ACLA-3, At1g09430), and two genes encode the ACLB subunit (ACLB-1, At3g06650 and ACLB-2, At5g49460). The ACLA and ACLB mRNAs accumulate in coordinated spatial and temporal patterns during plant development. This complex accumulation pattern is consistent with the predicted physiological needs for cytosolic acetyl-CoA, and is closely coordinated with the accumulation pattern of cytosolic acetyl-CoA carboxylase, an enzyme using cytosolic acetyl-CoA as a substrate. Taken together, these results indicate that ACL, encoded by the ACLA and ACLB genes of Arabidopsis, generates cytosolic acetyl-CoA. The heteromeric organization of this enzyme is common to green plants (including Chlorophyceae, Marchantimorpha, Bryopsida, Pinaceae, monocotyledons, and eudicots), species of fungi, Glaucophytes, Chlamydomonas, and prokaryotes. In contrast, all known animal ACL enzymes have a homomeric structure, indicating that a evolutionary fusion of the ACLA and ACLB genes probably occurred early in the evolutionary history of this kingdom.Acetyl-coenzyme A (CoA) is an intermediate metabolite that is juxtaposed between catabolic and anabolic processes. As the entry point for the tricarboxylic acid (TCA) cycle, acetyl-CoA can be considered the gateway in the oxidation of carbon derived from the catabolism of fatty acids, certain amino acids (e.g. Leu, Ile, Lys, and Trp), and carbohydrates. Furthermore, acetyl-CoA is the intermediate precursor for the biosynthesis of a wide variety of phytochemicals. Because membranes are impermeable to CoA derivatives, it can be inferred that acetyl-CoA is generated in at least four distinct metabolic pools representing the four subcellular compartments where acetyl-CoA metabolism occurs: plastids, mitochondria, peroxisomes, and the cytosol (Fig. 1). Therefore, plants should have distinct acetyl-CoA-generating systems in mitochondria (for the TCA cycle), in plastids (for de novo fatty acid biosynthesis), in peroxisomes (the product of ␤-oxidation of fatty acids), and in the cytosol (for the biosynthesis of isoprenoids, flavo...

show abstract

“…Hoffmann et al, 1980a;Inoue et al, 1966;Nelson & Rinne, 1975;Mattoo & Modi, 1970;Fritsch & Beevers, 1979). The enzyme, which is cytosolic, plays an important role in lipogenesis in many tissues by supplying the precursor acetyl-CoA units, which are themselves derived from intramitochondrial citrate (see Srere, 1975, for review).…”

Section: Introductionmentioning

confidence: 99%

Correlation of Lipid Accumulation in Yeasts with Possession of ATP: Citrate Lyase

Boulton

Ratledge

1981

Microbiology

View full text Add to dashboard Cite

ATP : citrate lyase has been found in 13 strains of yeast (representing six genera) which are capable of accumulating lipid to above 20% of their biomass. The enzyme is absent in 10 other yeasts which do not accumulate lipid. The presence of the enzyme is therefore directly correlated to the phenomenon of oleaginicity. The enzyme is located in the cytosol fraction of the yeasts and is probably the sole means of producing acetyl-CoA in most oleaginous yeasts. The specific activity of the enzyme correlates with the specific rate of lipid synthesis as determined in nitrogen-limited chemostat cultures of Lipomyces starkeyi, though not with the lipid content of the cells. From this and by calculation, it may be inferred that the enzyme is possibly the rate-limiting reaction for lipid biosynthesis.

show abstract

Citrate cleavage enzyme in mango fruit

Cited by 39 publications

References 8 publications

ATP Citrate Lyase from Germinating Castor Bean Endosperm

ATP Citrate Lyase from Germinating Castor Bean Endosperm

Molecular Characterization of a Heteromeric ATP-Citrate Lyase That Generates Cytosolic Acetyl-Coenzyme A in Arabidopsis,

Correlation of Lipid Accumulation in Yeasts with Possession of ATP: Citrate Lyase

Contact Info

Product

Resources

About