A molecular and biochemical analysis of the structure of the cyanogenic β-glucosidase (linamarase) from cassava (Manihot esculenta Cranz)

Hughes, Monica A.; Brown, Katharine A Robson; Pancoro, Adi; Murray, Brent S.; Oxtoby, Elli; Hughes, Jane

doi:10.1016/0003-9861(92)90518-2

Cited by 83 publications

(66 citation statements)

References 34 publications

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“…First, they are involved in the alteration of specific ␤-linked polysaccharides during cell expansion in development (Leah et al, 1995). Second, they are involved in pathogen defense reactions by cyanogenesis, wherein the enzymes catalyse the hydrolysis of glucosides after pathogen attack (Hughes et al, 1992). Third, ␤-glucosidases could release active cytokinins, gibberellins, and auxins from biologically inactive hormone-glucoside conjugates (Brzobohaty et al, 1993).…”

Section: The Time-specific Response Of Transcripts In Pokkalimentioning

confidence: 99%

Gene Expression Profiles during the Initial Phase of Salt Stress in Rice

et al. 2001

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Transcript regulation in response to high salinity was investigated for salt-tolerant rice (var Pokkali) with microarrays including 1728 cDNAs from libraries of salt-stressed roots. NaCl at 150 mM reduced photosynthesis to one tenth of the prestress value within minutes. Hybridizations of RNA to microarray slides probed for changes in transcripts from 15 min to 1 week after salt shock. Beginning 15 min after the shock, Pokkali showed upregulation of transcripts. Approximately 10% of the transcripts in Pokkali were significantly upregulated or downregulated within 1 hr of salt stress. The initial differences between control and stressed plants continued for hours but became less pronounced as the plants adapted over time. The interpretation of an adaptive process was supported by the similar analysis of salinity-sensitive rice (var IR29), in which the immediate response exhibited by Pokkali was delayed and later resulted in downregulation of transcription and death. The upregulated functions observed with Pokkali at different time points during stress adaptation changed over time. Increased protein synthesis and protein turnover were observed at early time points, followed by the induction of known stress-responsive transcripts within hours, and the induction of transcripts for defenserelated functions later. After 1 week, the nature of upregulated transcripts (e.g., aquaporins) indicated recovery.

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Section: The Time-specific Response Of Transcripts In Pokkalimentioning

confidence: 99%

Gene Expression Profiles during the Initial Phase of Salt Stress in Rice

et al. 2001

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“…10 The targeting of cancer cells with an antiplacental alkaline phosphatase antibody chemically conjugated to a broad substrate, sweet almond ␤-glucosidase, has been reported with promising results in vivo. 11 Recombinant fusion proteins are worth developing because they generally have advantages over chemically produced molecules in terms of product quality and yield.…”

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confidence: 99%

Antibody‐guided enzyme therapy of cancer producing cyanide results in necrosis of targeted cells

Kousparou¹,

Epenetos²,

Deonarain³

2002

Intl Journal of Cancer

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A number of enzyme/prodrug activation approaches for the treatment of cancer have been reported to date with varying success. We describe progress in the development of a system based on a ␤-glucosidase enzyme in combination with a naturally occurring "prodrug," the sugar linamarin, which releases the cytotoxin cyanide. A recombinant fusion protein, composed of an scFv (MFE-23) reactive against carcinoembryonic antigen (CEA) and a plant-derived ␤-glucosidase (linamarase), was produced and its cytotoxic potential was investigated. The fusion protein was expressed in a supersecretory mutant strain of Saccharomyces cerevisiae and purified by affinity chromatography. Extensive functional in vitro characterisation of the fusion protein showed that it retained antigen binding activity but that its catalytic activity was impaired, a problem not related to its fusion with the scFv. Nevertheless, we demonstrated complete tumour cell killing at doses of prodrug that are completely nontoxic to nontargeted cells. Preliminary in vivo characterisation showed that extensive glycosylation of the fusion protein caused its rapid clearance through the hepatic route. Aggregational properties also led to poor pharmacokinetics. Furthermore, we present some data analysing the mode of cell death resulting from exposure to this system. Enzymic catalysis of the substrate generates cyanide, a metabolic poison that asphyxiates cells and leads them to a necrotic-like cell death. This system has been called antibody-guided enzyme nitrile therapy (AGENT).

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“…We hypothesize that a substantial bystander killing effect of the cyanide would counteract the poor estimates (1-10%) for in vivo retroviral infection of solid tumors. The present work demonstrates that transduction of mouse, rat and human cells by retroviral vectors expressing the cassava linamarase gene, cas5, 9 drastically increases sensitivity of these cells to the cytotoxic effects of linamarin in vitro and in vivo. Neighboring cells can also be affected by the cyanide released, thereby amplifying the killing effect.…”

Section: Introductionmentioning

confidence: 64%

“…8 The enzyme encoded by this gene is a ␤-glucosidase that hydrolyzes the innocuous substrate linamarin (2-H0-isobutyronitrile-␤-d-glucopyranoside) to acetone cyanohydrin and glucose ( Figure 1a). 8,9 Acetone cyanohydrin is unstable at pH above 6 and spontaneously breaks down to acetone and HCN. 10 The cyanogenic glucoside, linamarin, is not hydrolyzed by most mammalian tissues, therefore once absorbed, in the absence of linamarase, it is excreted unchanged in the urine.…”

Section: Introductionmentioning

confidence: 99%

Successful use of a plant gene in the treatment of cancer in vivo

et al. 1998

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A new strategy for cancer gene therapy has been substrate, linamarin, followed by cell death. We show that developed using a plant gene which encodes the enzyme, the system can eradicate very large intracerebral gliomas linamarase, that hydrolyzes the cyanogenic glucoside subin vivo helped by a cyanide bystander effect. Animals strate, linamarin, into glucose, acetone and cyanide. Retroshowing a total regression of the tumor by magnetic resonviral vectors that carry linamarase as a potential killer-suicance imaging (MRI), do not show other appreciable toxic ide gene cause a marked sensitization to the innocuous effects.

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A molecular and biochemical analysis of the structure of the cyanogenic β-glucosidase (linamarase) from cassava (Manihot esculenta Cranz)

Cited by 83 publications

References 34 publications

Gene Expression Profiles during the Initial Phase of Salt Stress in Rice

Gene Expression Profiles during the Initial Phase of Salt Stress in Rice

Antibody‐guided enzyme therapy of cancer producing cyanide results in necrosis of targeted cells

Successful use of a plant gene in the treatment of cancer in vivo

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