Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D03345 (beta-Galactosidase)
 434 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The wild-type NAD(+)-dependent malic enzyme (dme) gene of Rhizobium (now Sinorhizobium) meliloti was cloned and localized to a 3.1 kb region isolated on the cosmid pTH69. This cosmid complemented the symbiotic nitrogen fixation (Fix-) phenotype of R. meliloti dme mutants. The dme gene was mapped by conjugation to between the cys-11 and leu-53 markers on the R. meliloti chromosome. beta-Galactosidase activities measured in bacterial strains carrying either dme-lacZ or tme-lacZ gene fusions (the tme gene encodes NADP(+)-dependent malic enzyme) indicated that the dme gene was expressed constitutively in free-living cells and in N2-fixing bacteroids whereas expression of the tme gene was repressed in bacteroids. The R. meliloti dme gene product (DME) was overexpressed in and partially purified from Escherichia coli. The properties of this enzyme, together with those of the NADP(+)-dependent malic enzyme (TME) partially purified from R. meliloti dme mutants, were determined. Acetyl-CoA inhibited DME but not TME activity. This result supports the hypothesis that DME, together with pyruvate dehydrogenase, forms a pathway in which malate is converted to acetyl-CoA.
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PMID:Properties of NAD(+)- and NADP(+)-dependent malic enzymes of Rhizobium (Sinorhizobium) meliloti and differential expression of their genes in nitrogen-fixing bacteroids. 904 24

The intercellular pheromone signal transduction pathways involved in sexual reproduction in the yeast Saccharomyces cerevisiae constitute an extracellular network system involving cell surface receptors. The system is analogous to the signaling pathway of mammalian peptide hormones. The yeast mating pheromone alpha factor is homologous to mammalian gonadoliberins such as luteinizing hormone-releasing hormone (LHRH). In this study, we used the yeast pheromone signaling pathway as a model system to evaluate the effect of industrial chemicals on mammalian peptide hormones. Haploid a- and alpha-cell types conjugate, using mating pheromones, to form diploid cells. However, in a cells treated with certain chemicals used in pesticides, fungicides, and industrial products (i.e., TPN (CAS No. 1897-45-6), thiuram (CAS No. 137-26-8), captan (CAS No. 133-06-2), oxine-copper (CAS No. 10380-28-6), zineb (CAS No. 12122-67-7), and ziram (CAS No. 137-30-4)) the induction of shmoo formation was suppressed even when commercial alpha-factor was added. The FUS1-lacZ gene, which is transcriptionally regulated by a pheromone, was transferred into yeast and the effects of TPN, captan, zineb, and ziram, under sublethal conditions, were investigated: beta-Galactosidase levels declined to levels similar to that of untreated control cells when in the absence of the alpha-factor. Furthermore, these chemicals influenced conjugation to alpha-cells, and mating efficiency declined as chemical concentration increased. Analysis of the yeast pheromone signaling pathway helps to establish chemical toxicity assay models for mammalian peptide signal transduction pathways.
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PMID:Yeast pheromone signaling pathway as a bioassay to assess the effect of chemicals on mammalian peptide hormones. 1457 75