Isozymes Of Superoxide Dismutase From Aloe Vera
Sabeh F; Wright T; Norton SJ
Department Of Biological Sciences, University Of North Texas
Enzyme Protein 49(4):212-21 1996

Extracts from the parenchymatous leaf gel and the rind of the Aloe vera plant (Aloe barbadensis Miller) were shown to contain seven electrophoretically-identifiable superoxide dismutases (SODs). The chromatographic elution profiles and the migration of these bands on native polyacrylamide gel electrophoresis (PAGE), for both the gel and rind, are quite similar. Two of these seven activities are insensitive to cyanide treatment, suggesting that they are mangano-SODs. The other five activities are sensitive to cyanide treatment, but insensitive to azide treatment and are presumed to be cupro-zinc SODs. All of the seven proteins appear to be homodimers with apparent native molecular masses centered at approximately 32 and 42 kD as indicated by SDS-PAGE and gel-filtration (FPLC) chromatography. The specific activities of SODs in the A. vera rind and gel are comparable to those of spinach leaves and of rabbit liver.

Aspergillus Nidulans verA Is Required For Production Of The Mycotoxin Sterigmatocystin
Keller NP; Kantz NJ; Adams TH
Department Of Plant Pathology & Microbiology, Texas A&M University
Appl Environ Microbiol Vol 60, ISS 5, 1994, P1444-50

Aspergillus nidulans produces the carcinogenic mycotoxin sterigmatocystin (ST), the next-to-last precursor in the aflatoxin (AF) biosynthetic pathway found in the closely related fungi Aspergillus flavus and Aspergillus parasiticus. We identified and characterized an A. nidulans gene, verA, that is required for converting the AF precursor versicolorin A to ST. verA is closely related to several polyketide biosynthetic genes involved in polyketide production in Streptomyces spp. and exhibits extended sequence similarity to A. parasiticus ver-1, a gene proposed to encode an enzyme involved in converting versicolorin A to ST. By performing a sequence analysis of the region 3’ to verA, we identified two additional open reading frames, designated ORF1 and ORF2. ORF2 is closely related to a number of cytochrome P-450 monooxygenases, while ORF1 shares identity with the gamma subunit of translation elongation factor 1. Given that several steps in the ST-AF pathway may require monooxygenase activity and that AF biosynthetic genes are clustered in A. flavus and A. parasiticus, we suggest that verA may be part of a cluster of genes required for ST biosynthesis. We disrupted the verA coding region by inserting the A. nidulans argB gene into the center of the coding region and transformed an A. nidulans argB2 mutant to arginine prototrophy. Seven transformants that produced DNA patterns indicative of a verA disruption event were grown under ST-inducing conditions, and all of the transformants produced versicolorin A but negligible amounts of ST (200-fold to almost 1,000-fold less than the wild type), confirming the hypothesis that verA encodes an enzyme necessary for converting versicolorin A to ST.

Purification & Characterization Of A Glutathione Peroxidase From The Aloe Vera Plant
Sabeh F; Wright T; Norton SJ
Dep. Biol. Sci., Univ. North Texas
Enzyme Protein (1994) Volume Date 1993, 47 (2), 92-8

Exts. from the parenchymous leaf-gel of the Aloe vera plant (Aloe barbadensis Miller) were shown to contain glutathione peroxidase (GSHPx) activity. The activity was purified to homogeneity by ion exchange and gel filtration (FPLC) chromatog. in the presence of 0.5 mM glutathione. The native enzyme has an apparent mol. wt. of 62 kD as detd. by gel filtration. In the presence of SDS, the mol. wt. was estd. to be about 16 kD as detd. by SDS-PAGE. The native enzyme is proposed to be constituted of four identical subunits; it also contains one atom of selenium per subunit, as found with most glutathione peroxidases from animal sources. The Km values were detd. to be 3.2 mM for glutathione and 0.26 mM for the hydroperoxide substrate, cumene hydroperoxide. The enzyme is competitively inhibited by N, S-bis-FMOC glutathione (Ki = 0.32 mM), a potent inhibitor of glyoxalase II. Inhibitors of glyoxalase I (e.g., S-octylglutathione) have no effect on the peroxidase activity.

Chemical Studies Of Aloe Vera Juice
Gjerstad, Gunnar; Bouchey GD
Quarterly Journal of Curde Drug Research 1968 Vol 964. p. 1451

In 1968, Gjerstad and Bouchey conducted a series of studies to determine the mineral constituents of Aloe vera and found the principal inorganic elements in the juice were calcium, chlorine, sodium, potassium, and manganese.

Then in 1971, the same two researchers conducted a study of amino acids present in Aloe vera juice, coming to the conclusion that it contained the mucopolysaccharides, glucose, and aldonentose, along with 18 of the 22 amino acids known to be necessary in the human body. They concluded further that one tablespoon of Aloe vera gel would contain in excess of 75 different chemical ingredients, although they identified few outside their occurrence in specified groupings.