Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A technique for the isolation of intact brush borders from rabbit renal cortex was evaluated. The procedure was monitored by phase and electron microscopy and marker enzymes, i.e. ATP:NMN adenylyl transferase, nuclear; cytochrome oxidase, mitochondrial; beta-glucuronidase, lysosomal; and glucose-6-Pase, microsomal; and indicated an essentially pure preparation of brush borders. The disaccharidase, trehalase, previously reported in renal tubules, was localized uniquely in brush borders. Maltase was also found; the specific activities of the two enzymes in the brush borders were increased 10- to 20-fold. Other disaccharidases, such as sucrase, isomaltase, lactase, and cellobiase, were absent. It is suggested that trehalase and maltase are appropriate candidates for marker enzymes of the renal brush border. Isolated brush borders possessed a ouabain-sensitive (Na(+) + K(+)) ATPase, an oligomycin-insensitive Mg(++) ATPase, and a Ca(++)-activated ATPase. Alkaline phosphatases, dephosphorylating beta-glycero-P, and trehalose-6-P were also present. The specific activities of these enzymes were increased three-to-five fold in the brush-border preparations; however, activities were found in other subcellular fractions of the renal cortex. Hexokinase, although evident in the isolated brush border, was found prominently associated with other membranous fractions. Phosphoglucomutase and UDPG pyrophosphorylase were localized in the soluble fraction of the renal cortex.
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PMID:Isolation and biochemical characterization of brush borders from rabbit kidney. 425 Jun 12

Sucrose synthase (SS) activity has been suggested to be a key point of regulation in nodule metabolism since this enzyme is down-regulated in response to different stresses which lead to decreased nitrogen fixation. In soybean, a dramatic decline of SS transcripts has been observed within 1 d from the onset of drought. Such a quick response suggests mediation by a signal transduction molecule. Abscisic acid (ABA) is a likely candidate to act as such a molecule as it mediates in a significant number of plant responses to environmental constraints. The hypothesis of ABA controlling nodule metabolism was approached in this work by assessing nodule responses to exogenous ABA supply in pea. Under the experimental conditions, ABA did not affect plant biomass, nodule numbers or dry weight. However, nitrogen fixation rate was reduced by 70% within 5 d and by 80% after 9 d leading to a reduced plant organic nitrogen content. Leghaemoglobin (Lb) content declined in parallel with that of nitrogen fixation. SS activity, however, was not affected by ABA treatment, and neither were the activities of the enzymes aspartate amino transferase, alkaline invertase, malate dehydrogenase, glutamate synthase, uridine diphosphoglucose pyrophosphorylase, isocitrate dehydrogenase, and glutamine synthetase. Nodule bacteroid-soluble protein content was reduced in nodules only after 9 d of ABA treatment. These results do not support the hypothesis that ABA directly regulates SS activity. However, they do suggest the occurrence of at least two different control pathways in nodules under environmental constraints, which include ABA being involved in a Lb/oxygen-related control of nitrogen fixation.
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PMID:Abscisic acid induces a decline in nitrogen fixation that involves leghaemoglobin, but is independent of sucrose synthase activity. 1128 73

An in situ study of enzymes involved in sucrose to hexose-phosphate conversion during in vitro stolon-to-tuber transition of potato (Solanum tuberosum L. cv. Bintje) was employed to follow developmental changes in spatial patterns. In situ activity of the respective enzymes was visualized by specific activity-staining techniques and they revealed distinct spatially and developmentally regulated patterns. Two of the enzymes studied were also subject to in situ investigations at the transcriptional level. During the stages of stolon formation high hexokinase (EC 2.7.1.1) and acid (cell wall-bound) invertase (EC 3.2.1.26) activities were restricted to the mitotically active (sub)apical region, suggesting a possible importance of these enzymes for cell division. At the onset of tuberization sucrose synthase (EC 2.4.1.13) and fructokinase (EC 2.7.1.4) were strongly induced (visualized at transcriptional and translational level) and the acid invertase activities disappeared from the swelling subapical region as expected. The high degree of similarity in the spatial pattern and the temporal induction of sucrose synthase and fructokinase suggests a tightly co-ordinated coarse (up)regulation, which may be subject to a sugar-modulated mechanism(s) by which genes involved in the metabolic sucrose-starch converting potential are co-ordinately regulated during tuber growth. The overall activity of uridine-5-diphosphoglucose pyrophosphorylase (EC 2.7.7.9) was present in all tissues during stolon and tuber development, implying that its coarse control is not subject to (in)direct developmental regulation.
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PMID:In situ analysis of enzymes involved in sucrose to hexose-phosphate conversion during stolon-to-tuber transition of potato. 1206 Feb 50