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PubMed2004

A case of peanut cross-allergy to lupine flour in a hot dog bread.

BACKGROUND: In a case monitored by the Norwegian National Register for Severe Allergic Reactions to Food, a patient with peanut allergy experienced an allergic reaction after eating a particular brand of hot dog bread. The aim of this study was to identify the eliciting allergen. METHODS: Extracts from the hot dog bread and reference material from peanut, lupine and lupine-fortified food products were analysed by immunochemical methods with patient serum and a new polyclonal anti-lupine antibody. RESULTS: Evidence could be provided that the hot dog bread contained proteins from lupine but not from peanut. CONCLUSION: Crossed peanut-lupine allergy can have clinical significance. A peanut-allergic patient reacted against hidden lupine protein in a hot dog bread. Presented with our results, the producer confirmed the use of lupine flour and changed the ingredient list.

Adult↗
PubMed1988

Quantitation of lectin binding sites in human colon mucins by use of peanut and wheat germ agglutinins.

We have developed a novel method for quantitation of lectin binding sites in mucins derived from colon tissues. Binding of peanut agglutinin and wheat germ agglutinin was measured in extracts from normal and malignant human colon epithelium. Binding of wheat germ agglutinin was used as an estimate of the total mucin present in the tissue extract. Peanut agglutinin was found to bind to mucin from normal colon, but at levels that may be difficult to appreciate by fluorescence microscopy. The yield of mucin extracted from colon cancer was more variable than that from normal colon, and the binding ratio of peanut agglutinin to wheat germ agglutinin was greater in extracts from tumors than in normal tissues. Our findings confirm the histological observation that peanut agglutinin binds more avidly to mucins from colon cancer than to those from normal colon. The finding of peanut agglutinin binding sites in mucins front normal colon was not expected. The quantitative technique may have detected small numbers of binding sites not readily appreciable by fluorescence microscopy. Alternatively, the chromatographic method for measuring lectin binding may be sufficiently sensitive to detect nonspecific binding of the lectin to terminal galactose residues other than the Thomsen-Friedenreich antigen.

Arachis↗
PubMed1989

Onset of expression of peanut lectin-binding glycoproteins is correlated with stratification of keratinocytes during human epidermal development in vivo and in vitro.

During gestation the epidermis develops from a single layer of ectoderm into a layer of keratinocytes overlaid by a layer of periderm; this is followed by a progressive increase in the number of layers of keratinocytes, until finally the distinct granular and cornified layers characteristic of mature epidermis are formed. As part of our investigation into the function of the peanut lectin-binding glycoproteins of cultured human keratinocytes, we have examined their expression at different stages of human epidermal development. We found that the onset of expression of the glycoproteins coincided with the transition from a two- to a three-layered epidermis, both in vivo and in organ culture. In adult epidermis, the patterns of binding of peanut lectin and Limax flavus lectin are complementary, with peanut binding more strongly to suprabasal keratinocytes and Limax flavus lectin binding more strongly to cells in the basal layer. We found that the complementary pattern of binding of the two lectins was established at, or shortly after, the onset of stratification and retained throughout development. In contrast, expression by keratinocytes of involucrin, a protein precursor of the cornified envelope, occurred after stratification had begun. Finally, we identified the peanut lectin-binding glycoproteins of adult epidermis by immunoblotting with an antiserum raised against the glycoproteins of cultured neonatal keratinocytes. In conclusion, expression of the peanut lectin-binding glycoproteins is an early event in epidermal development, and this would be consistent with a role for the glycoproteins in stratification.

Embryonic and Fetal Development↗
PubMed2005

Unconventional method based on circular dichroism to detect peanut DNA in food by means of a PNA probe and a cyanine dye.

In this paper we report an innovative and unconventional method based on circular dichroism for the identification of peanut DNA in food, which can be detected after PCR amplification at the nanomolar level by using an achiral PNA probe complementary to a tract of the peanut Ara h 2 gene and an achiral 3,3'-diethylthiadicarbocyanine dye [DiSC(2)(5)]. Peanuts are one of the most common causes of severe allergic reactions to foods and are particularly dangerous when they are "hidden" (undeclared) in food. For better protection of consumers, detection methods are required to specifically detect the presence of hidden allergens in a wide variety of food items. Alternative to the detection of the proteins is the determination of species-specific DNA, which is more resistant to technological treatments. PNAs are very specific probes able to recognize DNA sequences with high affinity and evidence for the binding can be obtained by using the DiSC(2)(5) dye, which aggregates onto the PNA-DNA duplex giving rise to a characteristic visibile band at 540 nm. Because the PNA-DNA duplex is in a right-handed helical conformation, the aggregation of the dye to the duplex gives also rise to a strong CD signal in the 500-600 nm region with a strong exciton coupling due to the formation of multimeric species, since the handedness of the helix is transferred to the dye aggregate. The dye does not interact with the free single-stranded DNA and although aggregating on the achiral PNA, this interaction is obviously not detectable by circular dichroism. Thus, only the formation of the PNA-DNA duplex, which takes place only upon specific Watson-Crick hydrogen binding between the PNA and the DNA bases, is detected, ensuring a very high specificity and sensitivity. The method has been optimized in a model system by using a synthetic oligonucleotide complementary to the PNA probe, showing that the intensity of the signal is linearly related to the amount of the DNA. The optimized method has been applied to the identification and quantitation of DNA extracted and amplified by PCR from peanuts and from peanut-containing foods, allowing for a very sensitive detection at a very low level (few pmol).

Arachis↗
PubMed2000

Use of modified BL21(DE3) Escherichia coli cells for high-level expression of recombinant peanut allergens affected by poor codon usage.

We previously cloned a panel of peanut allergens by phage display technology. Examination of the codons used in these sequences indicated that most of the cDNAs contain an excess of the least used codons in Escherichia coli, namely AGG/AGA, that correspond to a minor tRNA, the product of the dnaY gene. To achieve high-level expression of the peanut allergens, the cDNAs were subcloned into an expression vector of the pET series (Novagen) in order to produce (His)(10)-tagged fusion proteins in conventional E. coli BL21(DE3) cells. The peanut allergens Ara h 1, Ara h 2, and Ara h 6 with an AGG/AGA codon content of 8-10% were only marginally expressed, whereas the peanut profilin Ara h 5, with an AGG/AGA codon content of only 0.8%, was efficiently expressed in these cells. Hence, by using modified BL21(DE3) E. coli cells, namely BL21-CodonPlus(DE3)-RIL cells (Stratagene) with extra copies of E. coli argU, ileY, and leuW tRNA genes, it was possible to attain high-level expression of the proteins affected by rare codon usage. IPTG-induced expression of several recombinant peanut allergens, such as Ara h 1, Ara h 2, and Ara h 6, was greatly increased in these special cells compared to the expression yield achieved by conventional E. coli hosts. The purification of the soluble and the insoluble fraction of Ara h 2 was performed by metal-affinity chromatography and yielded a total of about 30 mg (His)(10)-tagged recombinant protein per liter of culture of transformed BL21(DE3)CodonPlus-RIL cells. This is over 100 times more than achieved by production of Ara h 2 in conventional BL21(DE3) cells.

2S Albumins, Plant↗
PubMed1992

Use of single-primer DNA amplifications in genetic studies of peanut (Arachis hypogaea L.).

A recent approach to detecting genetic polymorphism involves the amplification of genomic DNA using single primers of arbitrary sequence. When separated electrophoretically in agarose gels, the amplification products give banding patterns that can be scored for genetic variation. The objective of this research was to apply these techniques to cultivated peanut (Arachis hypogaea L.) and related wild species to determine whether such an approach would be feasible for the construction of a genetic linkage map in peanut or for systematic studies of the genus. Two peanut cultivars, 25 unadapted germplasm lines of A. hypogaea, the wild allotetraploid progenitor of cultivated peanut (A. monticola), A. glabrata (a tetraploid species from section Rhizomatosae), and 29 diploid wild species of Arachis were evaluated for variability using primers of arbitrary sequence to amplify segments of genomic DNA. No variation in banding pattern was observed among the cultivars and germplasm lines of A. hypogaea, whereas the wild Arachis species were uniquely identified with most primers tested. Bands were scored (+/-) in the wild species and the PAUP computer program for phylogenetic analysis and the HyperRFLP program for genetic distance analysis were used to generate dendrograms showing genetic relationships among the diploid Arachis species evaluated. The two analyses produced nearly identical dendrograms of species relationships. In addition, approximately 100 F2 progeny from each of two interspecific crosses were evaluated for segregation of banding patterns. Although normal segregation was observed among the F2 progeny from both crosses, banding patterns were quite complex and undesirable for use in genetic mapping. The dominant behavior of the markers prevented the differentiation of heterozygotes from homozygotes with certainty, limiting the usefulness of arbitrary primer amplification products as markers in the construction of a genetic linkage map in peanut.

Arachis↗
PubMed1996

Development of greenhouse screening for resistance to Aspergillus parasiticus infection and preharvest aflatoxin contamination in peanut.

Aspergillus flavus Link ex Fries and A. parasiticus Speare can invade peanut kernels and under certain environmental conditions produce unacceptable levels of the mycotoxin aflatoxin. A concerted effort is underway to reduce aflatoxin contamination in peanut and peanut products. A potentially effective method of control in peanut is the discovery and use of genes for resistance to either fungal invasion or aflatoxin formation. The objective of the present experimental study was to develop an effective and efficient procedure for screening individual plants or pods of single plants for resistance to invasion by the aflatoxigenic fungi and subsequent aflatoxin production. Methods of obtaining adequate drought-stress and fungal infection were developed through this series of experiments. By completely isolating the pods from the root zone and imposing drought-stress only on pegs and pods, high levels of fungal infection were observed. High amounts of preharvest aflatoxin accumulation were also produced by completely isolating the pods from the root zone. Mid-bloom inoculation with A. parasiticus-contaminated cracked corn and drought-stress periods of 40 to 60 days were the most effective procedures. This technique was used to assess peanut genotypes previously identified as being partially resistant to A. parasiticus infection or aflatoxin contamination, and segregating populations from four crosses. Variability in aflatoxin contamination was found among the 11 genotypes evaluated, however, none were significantly lower than the standard cultivars. Broad-sense heritability of four crosses was estimated through evaluation of seed from individual plants in the F2 generation. The heritability estimates of crosses GFA-2 x NC-V11 and Tifton-8 X NC-V11 were 0.46 and 0.29, respectively, but mean aflatoxin contamination levels were high (73,295 and 27,305 ppb). This greenhouse screening method could be an effective tool when genes for superior aflatoxin resistance are identified.

Aflatoxins↗
PubMed1975

Inhibition of growth of Aspergillus flavus and Trichoderma viride by peanut embryos.

Growth of Aspergillus flavus and Trichoderma viride on agar media was inhibited around embryos of green peanut seeds but not around embryos of cured seeds, intact peanut seeds, or testae. Both fungi were able to colonize intact seeds and testae. Substances inhibitory to A. flavus and T. viride were extracted with acetone from cotyledons of freshly harvested peanut seeds. Four compounds inhibitory to A. flavus were detected in crude acetone extracts. Three of the compounds demonstrated properties of phenolics. Results of this study suggest that inhibitory compounds in peanut cotyledons may play a role in protecting the peanut embryo from fungal infection.

Antifungal Agents↗
PubMed1994

Effect of Aspergillus parasiticus soil inoculum on invasion of peanut seeds.

Environmental control plots adjusted to late season drought and elevated soil temperatures were inoculated at peanut planting with low and high levels of conidia, sclerotia, and mycelium from a brown conidial mutant of Aspergillus parasiticus. Percentage infection of peanut seeds from undamaged pods was greatest for the subplot containing the high sclerotial inoculum (15/cm2 soil surface). Sclerotia did not germinate sporogenically and may have invaded seeds through mycelium. In contrast, the mycelial inoculum (colonized peanut seed particles) released large numbers of conidia into soil. Soil conidial populations of brown A. parasiticus from treatments with conidia and mycelium were positively correlated with the incidence of seed infection in undamaged pods. The ratio of A. flavus to wild-type A. parasiticus in soil shifted from 7:3 to 1:1 in the uninoculated subplot after instigation of drought, whereas in all subplots treated with brown A. parasiticus, the ratio of the two species became approximately 8:2. Despite high levels of brown A. parasiticus populations in soil, native A. flavus often dominated peanut seeds, suggesting that it is a more aggressive species. Sclerotia of wild-type A. parasiticus formed infrequently on preharvest peanut seeds from insect-damaged pods.

Aflatoxins↗
PubMed1990

Effects of roasting and storage on proteins and oil in peanut kernels.

Peanut kernels, untreated or soaked in salt solution, were roasted at 160 degrees C for 30 min in a hot air oven or oil roasted at 147 degrees C for 2 min and, stored at 27 degrees C and 5 degrees C up to 150 days. The heat treatments significantly decreased methionine, tryptophan and in vitro protein digestibility (IVPD) and, increased the soluble proteins and acid value of kernel oil. Storage of heated peanuts caused an increase in water-soluble proteins, IVPD, acid value and saponification value and a decrease in methionine, tryptophan and iodine value. The oil roasting was found to be more detrimental to nutritional quality and storage stability of peanuts as compared to dry roasting. The storage of heated peanuts at 5 degrees C was found to be beneficial in lowering the undesirable nutritional changes in the peanut kernels.

Arachis↗
PubMed2003

Microsatellite identification and characterization in peanut ( A. hypogaea L.).

A major constraint to the application of biotechnology to the improvement of the allotetraploid peanut, or groundnut ( Arachis hypogaea L.), has been the paucity of polymorphism among germplasm lines using biochemical (seed proteins, isozymes) and DNA markers (RFLPs and RAPDs). Six sequence-tagged microsatellite (STMS) markers were previously available that revealed polymorphism in cultivated peanut. Here, we identify and characterize 110 STMS markers that reveal genetic variation in a diverse array of 24 peanut landraces. The simple-sequence repeats (SSRs) were identified with a probe of two 27648-clone genomic libraries: one constructed using PstI and the other using Sau3AI/ BamHI. The most frequent, repeat motifs identified were ATT and GA, which represented 29% and 28%, respectively, of all SSRs identified. These were followed by AT, CTT, and GT. Of the amplifiable primers, 81% of ATT and 70.8% of GA repeats were polymorphic in the cultivated peanut test array. The repeat motif AT showed the maximum number of alleles per locus (5.7). Motifs ATT, GT, and GA had a mean number of alleles per locus of 4.8, 3.8, and 3.6, respectively. The high mean number of alleles per polymorphic locus, combined with their relative frequency in the genome and amenability to probing, make ATT and GA the most useful and appropriate motifs to target to generate further SSR markers for peanut.

Agriculture↗
PubMed2005

Select metal adsorption by activated carbon made from peanut shells.

Agricultural by-products, such as peanut shells, contribute large quantities of lignocellulosic waste to the environment each growing season; but few, if any, value-added uses exist for their disposal. The objective of this study was to convert peanut shells to activated carbons for use in adsorption of select metal ions, namely, cadmium (Cd2+), copper (Cu2+), lead (Pb2+), nickel (Ni2+) and zinc (Zn2+). Milled peanut shells were pyrolyzed in an inert atmosphere of nitrogen gas, and then activated with steam at different activation times. Following pyrolysis and activation, the carbons underwent air oxidation. The prepared carbons were evaluated either for adsorption efficiency or adsorption capacity; and these parameters were compared to the same parameters obtained from three commercial carbons, namely, DARCO 12x20, NORIT C GRAN and MINOTAUR. One of the peanut shell-based carbons had metal ion adsorption efficiencies greater than two of the three commercial carbons but somewhat less than but close to Minotaur. This study demonstrates that peanut shells can serve as a source for activated carbons with metal ion-removing potential and may serve as a replacement for coal-based commercial carbons in applications that warrant their use.

Adsorption↗
PubMed2005

Vinegar and peanut products as complementary foods to reduce postprandial glycemia.

Mealtime glycemic load is associated with risk for chronic disease. This study examined whether complementary foods (vinegar and peanut products) could lower postprandial glycemia without altering mealtime glycemic load. Eleven healthy subjects consumed two test meals (bagel and juice, glycemic load=81; or chicken and rice, glycemic load=48) under three conditions (control, vinegar, or peanut) using a randomized, crossover design. Vinegar or peanut ingestion reduced the 60-minute glucose response to both test meals by approximately 55%, but these reductions were significant only for the high-glycemic load meal. After consumption of the high-glycemic load meal, energy consumption for the remainder of the day was weakly affected by the vinegar and peanut treatments, a reduction of approximately 200 to 275 kcal (P=.111). Regression analyses indicated that 60-minute glucose response to the test meals explained 11% to 16% of the variation in later energy consumption. In conclusion, the addition of vinegar or peanut products to a high-glycemic load meal significantly reduced postprandial glycemia.

Acetic Acid↗
PubMed2004

Growth promotion and yield enhancement of peanut (Arachis hypogaea L.) by application of plant growth-promoting rhizobacteria.

Although plant growth-promoting rhizobacteria (PGPR) have been reported to influence plant growth, yield and nutrient uptake by an array of mechanisms, the specific traits by which PGPR promote plant growth, yield and nutrient uptake were limited to the expression of one or more of the traits expressed at a given environment of plant-microbe interaction. We selected nine different isolates of PGPR from a pool of 233 rhizobacterial isolates obtained from the peanut rhizosphere on the basis of ACC-deaminase activity. The nine isolates were selected, initially, on the basis of germinating seed bioassay in which the root length of the seedling was enhanced significantly over the untreated control. All the nine isolates were identified as Pseudomonas spp. Four of these isolates, viz. PGPR1, PGPR2, PGPR4 and PGPR7 (all fluorescent pseudomonads), were the best in producing siderophore and indole acetic acid (IAA). In addition to IAA and siderophore-producing attributes, Pseudomonas fluorescens PGPR1 also possessed the characters like tri-calcium phosphate solubilization, ammonification and inhibited Aspergillus niger and A. flavus in vitro. P. fluorescens PGPR2 differed from PGPR1 in the sense that it did not show ammonification. In addition to the traits exhibited by PGPR1, PGPR4 showed strong in vitro inhibition to Sclerotium rolfsii. The performances of these selected plant growth-promoting rhizobacterial isolates were repeatedly evaluated for 3 years in pot and field trials. Seed inoculation of these three isolates, viz. PGPR1, PGPR2 and PGPR4, resulted in a significantly higher pod yield than the control, in pots, during rainy and post-rainy seasons. The contents of nitrogen and phosphorus in soil, shoot and kernel were also enhanced significantly in treatments inoculated with these rhizobacterial isolates in pots during both the seasons. In the field trials, however, there was wide variation in the performance of the PGPR isolates in enhancing the growth and yield of peanut in different years. Plant growth-promoting fluorescent pseudomonad isolates, viz. PGPR1, PGPR2 and PGPR4, significantly enhanced pod yield (23-26%, 24-28% and 18-24%, respectively), haulm yield and nodule dry weight over the control in 3 years. Other attributes like root length, pod number, 100-kernel mass, shelling out-turn and nodule number were also enhanced. Seed bacterization with plant growth-promoting P. fluorescens isolates, viz. PGPR1, PGPR2 and PGPR4, suppressed the soil-borne fungal diseases like collar rot of peanut caused by A. niger and PGPR4 also suppressed stem rot caused by S. rolfsii. Studies on the growth patterns of PGPR isolates utilizing the seed leachate as the sole source of C and N indicated that PGPR4 isolate was the best in utilizing the seed leachate of peanut, cultivar JL24. Studies on the rhizosphere competence of the PGPR isolates, evaluated on the basis of spontaneous rifampicin resistance, indicated that PGPR7 was the best rhizoplane colonizer and PGPR1 was the best rhizosphere colonizer. Although the presence of growth-promoting traits in vitro does not guarantee that an isolate will be plant growth promoting in nature, results suggested that besides ACC-deaminase activity of the PGPR isolates, expression of one or more of the traits like suppression of phytopathogens, solubilization of tri-calcium phosphate, production of siderophore and/or nodulation promotion might have contributed to the enhancement of growth, yield and nutrient uptake of peanut.

Arachis↗
PubMed2004

Genomic organization of peanut allergen gene, Ara h 3.

Type 1 hypersensitivity to peanut proteins is a well-recognized health problem. Several peanut seed storage proteins have been identified as allergens. Ara h 3, a glycinin protein, is one of the important peanut allergens. Although amino acid and cDNA sequences are available for Ara h 3, there is not information at the genomic level. The objectives of this study were to isolate, sequence, and characterize the genomic clone of peanut allergen, Ara h 3. A peanut genomic library was screened, using two [32P] end-labeled oligonucleotide probes designed based on cDNA sequences of Ara h 3 and Ara h 4. Four positives lambda FIX II clones were obtained after four rounds of screenings. Digestion with Sac I resulted in two fragments of 1.5 and 10 kb hybridizing to the probes. Both fragments were subcloned into p-Bluescript vector and sequenced. The Ara h 3 gene spans 3.5 kb and consists of four exons, three introns, 5' and 3' flanking regions. The open reading frame is 2008 bp long and can encode a polypeptide of 538 amino acids residues. Sequences analogous to a TATA-box (TATAAAT), CAAT-box (AGGA), G-box (TCCTACGTGTCC) and several cis-elements were found in the promoter region. In the 3' downstream region, three polyadenylation signals (AATAAA) were identified.

Allergens↗
PubMed2006

Lipid profile of rats fed high-fat diets based on flaxseed, peanut, trout, or chicken skin.

OBJECTIVE: Dietary saturated fatty acids are associated with coronary disease. Conversely, dietary monounsaturated polyunsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) seem to exert a protective effect. This study evaluated the lipid profile of rats fed high-fat (HF) diets, with fat added as different sources of PUFA (flaxseed and trout), MUFA (peanut), and saturated fatty acid (chicken skin). METHODS: Adult male Wistar rats were placed into six dietary groups (n = 10): control (normal); high fat, with 1% cholesterol, 10% soy oil, and 5% lard; and four groups fed similar HF diets, with 10% lipid as trout, flaxseed, peanut, or chicken skin. After 28 d the animals were killed. Blood, livers, and adipose tissue samples were collected. RESULTS: A higher level (P < 0.05) of total serum cholesterol was observed in rats fed the normal diet (93.57 +/- 14.95 mg/dL) compared with those fed the HF diet (67.57 +/- 12.54 mg/dL). Total cholesterol levels in rats fed the flaxseed diet were lower (P < 0.05) than in rats fed the other fats. No difference was observed in cholesterol levels between groups fed the peanut and chicken skin diets (P > 0.05). Animals fed the peanut diet showed decreased body weight gain than did animals in the other treatment groups. There were large lipid and cholesterol depositions in livers of rats fed the HF diet. Lipid deposition in adipose tissue followed the same dietary fatty acid profile, i.e., high levels of omega-3 PUFA in the flaxseed group, high levels of MUFA in the peanut and chicken skin groups and high levels of omega-6 PUFA in the trout group. CONCLUSIONS: These data indicate that flaxseed is promising for dietary manipulation of hyperlipidemia.

Adipose Tissue↗
PubMed2003

Determination of aflatoxins in peanuts by matrix solid-phase dispersion and liquid chromatography.

A new method based on matrix solid-phase dispersion (MSPD) extraction was studied to determine aflatoxin B1, B2, G1 and G2 from peanuts. Optimization of different parameters, such as type of solid supports for matrix dispersion and elution solvents were carried out. The method used 2 g of peanut sample, 2 g of C18 bonded silica as MSPD sorbent and acetonitrile as eluting solvent. Recoveries of each aflatoxin spiked to peanut samples at 2.5 ng/g (5 ng/g for aflatoxin G2) level were between 78 and 86% with relative standard deviations ranging from 4 to 7%. The limits of quantification ranged from 0.125 to 2.5 ng/g for the four studied aflatoxins using liquid chromatography (LC) with fluorescence detection. In addition, LC coupled to mass spectrometry with an electrospray interface was used for confirmation of aflatoxins present in real samples. Eleven peanut samples from different countries were analyzed by the proposed method and by using an enzyme-linked immunosorbent assay (ELISA). ELISA test is a good screening method for investigation of these mycotoxins in peanut samples.

Aflatoxins↗
PubMed1997

Regulation of peanut glutamate dehydrogenase by methionine sulphoximine.

Peanut glutamate dehydrogenase (GDH) was electrophoretically purified to homogeneity. Rotofor IEF fractionated the peanut GDH to 7 isoelectric (charge) isomers, which focused in the pH 5-8 range. Western blot analysis of the charge isomers using anti-GDH serum showed that methionine sulphoximine (MSX) treatment suppressed the b-subunit (69 KDa), but enhanced the a-subunit (45 KDa), and alpha-subunit (46 KDa) of the enzyme. The MSX-mediated suppression of the b-subunit increased the NH4+ Km value of the acidic charge isomers from 7.7 mM in the control to 50 mM in the MSX-treated peanut, and also increased the 2-ketoglutarate Km value of the basic charge isomers from 0.4 mM in the control to 7.0 mM in the MSX treatment. Therefore, the control peanut could salvage NH4+ with its GDH activity. But by increasing the NH4+ Km value, the MSX rendered the enzyme ineffective in NH4+ salvage. In the deamination direction, despite the enhancement of the a-, and alpha-subunits by MSX, the basic charge isomers of GDH had very high Km value for L-glu (50 mM), similar to that (25 mM) of the control. Thus, the GDHs of the control, and MSX treatment could not function in the deamination reaction in vivo. These results show that the treatment of peanut with MSX impaired the amination function of GDH.

Arachis↗