Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The beta-glucosidase from Aspergillus niger (CMI CC 324262) was purified, and an N-terminal sequence and two internal sequences were determined. BglI genomic gene and the cDNA were cloned from a genomic library and by reverse transcriptase-polymerase chain reaction, respectively. The cDNA was successfully expressed in Saccharomyces cerevisiae and Pichia pastoris. Sequence analysis revealed that the gene encodes a 92-kDa enzyme that is a member of glycosidase family 3. (1)H-NMR analysis of the reaction catalyzed by this enzyme confirmed that, in common with other family 3 glycosidases, this enzyme hydrolyzes with net retention of anomeric configuration. Accordingly, the enzyme was inactivated by 2-deoxy-2-fluoro beta-glucosyl fluoride, with kinetic parameters of k(i) = 4.5 min(-1), K(I) = 35.4 mM, through the trapping of a covalent glycosyl enzyme intermediate. The catalytic competence of this intermediate was demonstrated by the fact that incubation with linamarin resulted in reactivation, presumably via a transglycosylation mechanism. Peptic digestion of the 2-deoxy-2-fluoroglucosyl enzyme and subsequent analysis of high pressure liquid chromatography eluates by electrospray ionization triple quadrupole mass spectrometry in the neutral loss mode allowed the localization of a 2-deoxy-2-fluoroglucosyl-peptide. Sequence determination of this labeled peptide by tandem mass spectrometry in the daughter ion scan mode permitted the identification of Asp-261 as the catalytic nucleophile within the sequence VMSDW. Asp-261 is fully conserved within this family, consistent with its key role, and aligns with the aspartic acid residue previously identified in the Aspergillus wentii enzyme by labeling with conduritol B epoxide (Bause, E., and Legler, G. (1974) Hoppe-Seyler's Z. Physiol. Chem. 355, 438-442).
...
PMID:Cloning, expression, characterization, and nucleophile identification of family 3, Aspergillus niger beta-glucosidase. 1067 36

In certain maize genotypes (nulls), beta-glucosidase does not enter the gel and therefore cannot be detected on zymograms. Such genotypes were initially thought to be homozygous for a null allele at the glu1 gene. We have shown that a beta-glucosidase aggregating factor (BGAF) is responsible for the null phenotype, and it specifically interacts with maize beta-glucosidases and forms large insoluble aggregates. To understand the mechanism of the beta-glucosidase-BGAF interaction, we constructed chimeric enzymes by domain swapping between the maize beta-glucosidase isozymes Glu1 and Gu2, to which BGAF binds, and the sorghum beta-glucosidase (dhurrinase) isozyme Dhr1, to which BGAF does not bind. The results of binding assays with 12 different chimeric enzymes showed that an N-terminal region (Glu(50)-Val(145)) and an extreme C-terminal region (Phe(466)-Ala(512)) together form the BGAF binding site on the enzyme surface. In addition, we purified BGAF, determined its N-terminal sequence, amplified the BGAF cDNA by reverse transcriptase-polymerase chain reaction, expressed it in Escherichia coli, and showed that it encodes a protein whose binding and immunological properties are identical to the native BGAF isolated from maize tissues. A data base search revealed that BGAF is a member of the jasmonite-induced protein family. Interestingly, the deduced BGAF sequence contained an octapeptide sequence (G(P/R)WGGSGG) repeated twice. Each of these repeat units is postulated to be involved in forming a site for binding to maize beta-glucosidases and thus provides a plausible explanation for the divalent function of BGAF predicted from binding assays.
...
PMID:Identification of beta-glucosidase aggregating factor (BGAF) and mapping of BGAF binding regions on Maize beta -glucosidase. 1109 99

A variety of milk proteins including lactoferrin, angiogenin-1, alpha-lactalbumin, beta-lactoglobulin, lactoperoxidase, casein and the novel whey proteins lactogenin and glycolactin were tested for inhibitory activity toward human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT), alpha-glucosidase, beta-glucosidase and beta-glucuronidase. Lactoferrin exerted the most potent inhibitory action with an IC50 of about 6 microM. Lactoperoxidase, lactogenin, angiogenin-1 and glycolactin inhibited HIV-1 RT activity with decreasing potencies. Beta-lactoglobulin, alpha-lactalbumin and casein displayed little or no inhibitory effect. Succinylation with succinic anhydride augmented the inhibitory effect of glycolactin, beta-lactoglobulin, alpha-lactalbumin, casein and human lactoferrin. The inhibitory effect of the various milk proteins on the activities of alpha-glucosidase, beta-glucosidase and beta-glucuronidase was meager. Succinylation tended to increase the alpha-glucosidase-inhibitory effect of milk proteins but neither their beta-glucosidase-inhibitory nor beta-glucuronidase-inhibitory effect was affected.
...
PMID:First demonstration of an inhibitory activity of milk proteins against human immunodeficiency virus-1 reverse transcriptase and the effect of succinylation. 1110 90

From the fruiting bodies of the edible mushroom Flammulina velutipes a single-chained ribosome inactivating protein with a molecular weight of 13.8 kDa was isolated with a procedure involving ion exchange chromatography on DEAE-cellulose and SP-Sepharose and affinity chromatography on Affi-gel blue gel. The protein was novel in that it possessed a molecular weight lower than those of previously reported RIPs and that it was capable of inhibiting human immunodeficiency virus (HIV-1) reverse transcriptase, beta-glucosidase and beta-glucuronidase. Its N-terminal sequence exhibited a certain degree of similarity to those of plant ribosome inactivating proteins.
...
PMID:Isolation and characterization of velutin, a novel low-molecular-weight ribosome-inactivating protein from winter mushroom (Flammulina velutipes) fruiting bodies. 1132 20

A protein designated hypogin, with a prominent suppressive action on the growth of the fungi Mycosphaerella arachidicola, Fusarium oxysporum and Coprinus comatus, was isolated from seeds of the peanut Arachis hypogaea. The protein inhibited human immunodeficiency virus (HIV) reverse transcriptase and enzymes associated with HIV infection including alpha-glucosidase and beta-glucosidase. The proliferative response of mouse splenocytes was attenuated in the presence of the protein. The protein exhibited a molecular mass of 7.2 kDa in tricine gel electrophoresis and gel filtration on Superdex 75 and an N-terminal sequence resembling peanut allergen Ara H1. The isolation procedure involved affinity chromatography on Affi-gel blue gel and ion-exchange chromatography on CM-Sepharose. The protein was adsorbed in both chromatographic media.
...
PMID:Hypogin, a novel antifungal peptide from peanuts with sequence similarity to peanut allergen. 1132 90

From the roots of the Chinese medicinal herb Pseudostellaria heterophylla a single-chained lectin with a molecular weight of 36 kDa and high hemagglutinating activity was isolated. The lectin was adsorbed on DEAE-cellulose in 10 mM Tris-HCI buffer (pH 7.4) and was eluted by the same buffer containing 50 mM NaCl. It was adsorbed on SP-Sepharose in 10mM NH4OAc (pH 4.5) and eluted by approximately 0.5 M NaCl in the same buffer. The hemagglutinating activity of the lectin could not be inhibited by a large variety of monosaccharides, but was largely abrogated by exposure to 0.05 M HCl, 0.05M NaOH or 80 degrees C. However, about 50% of the activity remained after exposure to 0.025M NaOH or 40 degrees C. Despite possession of an N-terminal sequence exhibiting some similarity to thaumatin-like proteins with antifungal activity, the lectin was devoid of antifungal activity. The lectin exerted some inhibitory effect on the glycohydrolases alpha-glucosidase, beta-glucosidase and beta-glucuronidase which are involved in HIV infection but had no suppressive action on human immunodeficiency virus-type 1 reverse transcriptase.
...
PMID:A novel lectin from Pseudostellaria heterophylla roots with sequence simularity to Kunitz-type soybean trypsin inhibitor. 1144 23

A variety of lectins were tested in vitro for inhibitory action against the activities of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase and the N-glycohydrolases (alpha-glucosidase, beta-glucosidase and beta-glucuronidase). Lectins from Phaseolus vulgaris, Momordica charantia, Ricinus communis and its constituent chains, and Agaricus bisporus were able to inhibit HIV-1 reverse transcriptase. P. vulgaris lectin and A. bisporus lectin were the most potent. The aforementioned lectins had only weak or no inhibitory effects on the glycohydrolases. The inhibitory effect of polysaccharopeptide from the mushroom Coriolus versicolor on HIV-1 reverse transcriptase and alpha-glucosidase was enhanced after chemical modification with chlorosulfonic acid. However, the inhibitory effect of the algal polysaccharide fucoidan on HIV-1 reverse transcriptase and alpha-glucosidase was not augmented by sulfation. Trypsin inhibitors from Phaseolus lunatus and Glycine max, gossypol and alkaloids from Corydalis yanhusuo were able to inhibit HIV-1 reverse transcriptase. Dicoumarol was capable of inhibiting HIV-1 reverse transcriptase, alpha-glucosidase, beta-glucosidase and beta-glucuronidase.
...
PMID:Examination of lectins, polysaccharopeptide, polysaccharide, alkaloid, coumarin and trypsin inhibitors for inhibitory activity against human immunodeficiency virus reverse transcriptase and glycohydrolases. 1158 48

A novel antifungal protein with its N-terminal sequence bearing similarity to the C-terminal sequences of peroxidases was isolated from French bean legumes. The protein, which possessed a molecular weight of 37 kDa, was adsorbed on Affi-gel blue gel and CM-Sepharose. The protein exhibited peroxidase activity with a Km of 58 microM and a Vmax of 3.36 U/nmol. Optimal peroxidase activity was found at 22 degrees C and pH 4. It exerted antifungal activity against a variety of fungal species including Coprinus comatus, Mycosphaerella arachidicola, Fusarium oxysporum and Botrytis cinerea. It inhibited the activities of alpha-glucosidase and beta-glucosidase but was without any inhibitory effect on HIV-1 reverse transcriptase.
...
PMID:Isolation of a novel peroxidase from French bean legumes and first demonstration of antifungal activity of a non-milk peroxidase. 1213 13

A screening process was applied to extracts made from Sutherlandia frutescens (L.) R. Br (Fabaceae) and Lobostemon trigonus (Boraginaceae) as identified by the Botany Department, University of Port Elizabeth to detect if any of the extracts inhibited the human immunodeficiency virus (HIV). For purposes of dereplication, sulphated polysaccharides were removed and bovine serum albumin (BSA) was included in the assays to adsorb non-specific tannins potentially present. In the reverse transcriptase (RT) assay, an aqueous extract of the Lobostemon leaves inhibited HIV-1 RT with an IC50 value of 49 microg/ml, while in the protease assay no inhibition was seen. In the alpha- and beta-glucosidase assays, no significant inhibition was seen with the inclusion of BSA, indicating tannin-based inhibitory effects on these two enzymes. The beta-glucuronidase inhibitory activity, however, was retained in the presence of BSA. The study shows that Sutherlandia extracts contain inhibitory compounds active against HIV target enzymes, while aqueous Lobostemon leaf extracts contain a potent HIV-1 RT inhibitor, thus showing a potential mechanistic action of these plants in aiding HIV-positive patients.
...
PMID:Anti-HIV activities of organic and aqueous extracts of Sutherlandia frutescens and Lobostemon trigonus. 1558 58

Production of cellulolytic enzymes, such as cellobiohydrolases (CBH) and cellobiose dehydrogenase (CDH), by the basidiomycete Phanerochaete chrysosporium is significantly repressed in glucose-containing media; this is known as carbon catabolite repression. We have analyzed the glucose concentration dependence of transcript numbers of the cellulolytic genes (cel6A, cel7D, and cdh) and beta-glucosidase gene (bgl3A) by means of real-time quantitative reverse transcriptase polymerase chain reaction to investigate the roll of carbon catabolite derepression in these gene expression. When the mycelium of P. chrysosporium grown in glucose culture was transferred to media containing various concentrations of glucose (0-5,000 microM), the expression levels of cel6A, cel7D, and cdh were drastically influenced by glucose, whereas no significant change was observed in bgl3A. The numbers of transcripts of cel6A, cel7D, and cdh increased exponentially during incubation for 6 h in the culture without glucose, and the rates of increase were 2.1 times per hour for cel6A transcripts and 2.7 times per hour for cel7D transcripts. Moreover, derepression of cel6A and cel7D was delayed (by 1.6 and 0.6 h, respectively) when the culture contained 50 microM glucose compared with that in the absence of glucose, suggesting that the promoter activities of cel7D and cel6A are distinct under conditions of carbon catabolite derepression.
...
PMID:Real-time quantitative analysis of carbon catabolite derepression of cellulolytic genes expressed in the basidiomycete Phanerochaete chrysosporium. 1856 9


1 2 Next >>

---