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)

Activities of NAD(+)-dependent sorbitol dehydrogenase (SDH), sorbitol oxidase (SOX), sucrose synthase (SS), acid invertase (AI), and neutral invertase (NI) in 'Encore' peach (Prunus persica L.) fruits and developing shoot tips were assayed during the growing season to determine whether carbohydrate metabolizing enzymes could serve as indicators of sink strength. In fruit flesh, SS activity was detected during Stage I of growth, when cells were actively dividing, and SDH activity was detected during Stage III, when cells were actively enlarging. Acid invertase activity was detected during Stage I and showed a closer correlation with relative increase in fruit weight during the growing season than SS activity. During seed filling and pit hardening (Stage II), when relative fruit growth rate was slowest, activities of carbohydrate metabolizing enzymes in fruit flesh were not detectable. No SOX activity was detected during Stages I and II. The highest sucrose content occurred near the end of fruit development when the activities of sucrose metabolizing enzymes were low. In developing shoot tips, the sorbitol:sucrose ratio was 2:1 (w/w) and SDH activity was low at the beginning and end of the season when vegetative growth was slowest. The sorbitol:sucrose ratio changed to 1:1 (w/w) along with an increase in SDH activity in shoot tips during the mid-growing season. In 'Nemaguard' peach, SDH exhibited higher activity in root tips than in other organs. Among the sorbitol- and sucrose-metabolizing enzyme activities, only SDH activity was positively correlated with shoot growth in 'Nemaguard' plants.
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PMID:Carbohydrate metabolism of vegetative and reproductive sinks in the late-maturing peach cultivar 'Encore' 1265 89

A biohydrogen production system coupling the polysaccharide such as sucrose and maltose degradation with invertase and glucose dehydrognase (GDH) and hydrogen production with colloidal platinum as hydrogen-evolved catalyst using the visible light-induced photosensitization of water-soluble zinc porphyrin, zinc tetraphenylporphyrin tetrasulfonate (ZnTPPS) has been investigated. Continuous hydrogen gas production was observed when the sample solution containing polysaccharide, invertase, GDH, nicotinamide adenine dinucreotide (NAD(+)), ZnTPPS, methylviologen (an electron relay reagent), and colloidal platinum was irradiated by visible light. After 240-min irradiation, the amount of hydrogen production in the system using sucrose and maltose was estimated to be 3.1 and 0.35 micromol, respectively.
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PMID:Bio-mimetic hydrogen production from polysaccharide using the visible light sensitization of zinc porphyrin. 1267 71

Whiteflies accumulate the polyhydric alcohol, sorbitol, when exposed to temperatures greater than about 30 degrees C. Feeding experiments using artificial diets containing labeled sucrose showed that more of the label was incorporated into whitefly bodies and less was excreted in the honeydew when feeding was conducted at 41 compared with 25 degrees C. Analysis of the components of the honeydew showed that more of the excreted label was in glucose and fructose and less in trehalulose at 41 degrees C than at 25 degrees C. A similar effect of temperature on honeydew composition occurred for whiteflies feeding on cotton leaves. Measurement of the activities of glycolytic, pentose-phosphate and polyol pathway enzymes at 30 and 42 degrees C showed that NADPH-dependent ketose reductase/sorbitol dehydrogenase (NADPH-KR/SDH), sucrase, glucokinase and glucose-6-phosphate dehydrogenase activities were stimulated to a greater extent at 42 degrees C than trehalulose synthase and fructokinase. NAD(+)-sorbitol dehydrogenase (NAD(+)-SDH) activity was inhibited at 42 degrees C. We propose that high temperature alters metabolic activity in a way that increases the availability of fructose and stimulates pentose-phosphate pathway activity, providing both the substrate and coenzyme for sorbitol synthesis. High temperature also increases the activity of NADPH-KR/SDH, the enzyme in whiteflies that synthesizes sorbitol, but inhibits the activity of NAD(+)-SDH, the enzyme that degrades sorbitol.
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PMID:Effect of high temperature on the metabolic processes affecting sorbitol synthesis in the silverleaf whitefly, Bemisia argentifolii. 1277 Mar 92

Vegetative buds of peach (Prunus persica L. Batsch.) trees act as strong sinks and their bud break capacity can be profoundly affected by carbohydrate availability during the rest period (November-February). Analysis of xylem sap revealed seasonal changes in concentrations of sorbitol and hexoses (glucose and fructose). Sorbitol concentrations decreased and hexose concentrations increased with increasing bud break capacity. Sucrose concentration in xylem sap increased significantly but remained low. To clarify their respective roles in the early events of bud break, carbohydrate concentrations and uptake rates, and activities of NAD-dependent sorbitol dehydrogenase (SDH), sorbitol oxidase (SOX) and cell wall invertase (CWI) were determined in meristematic tissues, cushion tissues and stem segments. Only CWI activity increased in meristematic tissues shortly before bud break. In buds displaying high bud break capacity (during January and February), concentrations of sorbitol and sucrose in meristematic tissues were almost unchanged, paralleling their low rates of uptake and utilization by meristematic tissues, and indicating that sorbitol and sucrose play a negligible role in the bud break process. Hexose concentrations in meristematic tissues and glucose imported by meristematic tissues correlated positively with bud break capacity, suggesting that hexoses are involved in the early events of bud break. These findings were confirmed by data for buds that were unable to break because they had been collected from trees deprived of cold. We therefore conclude that hexoses are of greater importance than sorbitol or sucrose in the early events of bud break in peach trees.
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PMID:Trophic control of bud break in peach (Prunus persica) trees: a possible role of hexoses. 1499 62

Tissue distribution and activity of enzymes involved in sucrose and hexose metabolism were examined in kernels of two inbreds of maize (Zea mays L.) at progressive stages of development. Levels of sugars and starch were also quantitated throughout development. Enzyme activities studied were: ATP-linked fructokinase, UTP-linked fructokinase, ATP-linked glucokinase, sucrose synthase, UDP-Glc pyrophosphorylase, UDP-Glc dehydrogenase, PPi-linked phosphofructokinase, ATP-linked phosphofructokinase, NAD-dependent sorbitol dehydrogenase, NADP-dependent 6-P-gluconate dehydrogenase, NADP-dependent Glc-6-P dehydrogenase, aldolase, phosphoglucoisomerase, and phosphoglucomutase. Distribution of invertase activity was examined histochemically. Hexokinase and ATP-linked phosphofructokinase activities were the lowest among these enzymes and it is likely that these enzymes may regulate the utilization of sucrose in developing maize kernels. Most of the hexokinase activity was found in the endosperm, but the embryo had high activity on a dry weight basis. The endosperm, which stores primarily starch, contained high PPi-linked phosphofructokinase and low ATP-linked phosphofructokinase activities, whereas the embryo, which stores primarily lipids, had much higher ATP-linked phosphofructokinase activity than did the endosperm. It is suggested that PPi required by UDP-Glc pyrophosphorylase and PPi-linked phosphofructokinase in the endosperm may be supplied by starch synthesis. Sorbitol dehydrogenase activity was largely restricted to the endosperm, whereas 6-P-gluconate and Glc-6-P dehydrogenase activities were highest in the base and pericarp. A possible metabolic pathway by which sucrose is converted into starch is proposed.
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PMID:Enzymes of sucrose and hexose metabolism in developing kernels of two inbreds of maize. 1666 24

The first step in sucrose use by maize kernels produces fructose, regardless of whether the initial reaction is catalyzed by an invertase or the reversible sucrose synthase. This fructose can enter subsequent metabolism via hexokinase, or in maize kernels, by a sorbitol dehydrogenase that reversibly converts fructose + NADH to sorbitol + NAD. High levels of SDH activity suggest that kernels synthesize considerable amounts of sorbitol, but the molecular mechanism and functional role for this process have remained equivocal. To gain insights on the role of sorbitol synthesis in maize endosperm we cloned and characterized the transcriptional control of the maize sorbitol dehydrogenase (Sdh1) gene. Data indicated that Sdh1 was essentially kernel- and endosperm-specific, with maximal expression at both the mRNA and enzyme activity levels during early kernel development. Expression was elevated in high-sugar mutants (sugary1, shrunken2), also by sugar injections, and was more pronounced when transfected tissues were incubated at low oxygen concentrations. Control of Sdh1 expression in our transient assays was largely dependent on the first intron of Sdh1. We speculate that SDH activity may represent an adaptation to the high-sugar/low-oxygen environment of the endosperm. Under these conditions, the NADH-dependent reduction of fructose to sorbitol would regenerate NAD[+], thus contributing to the maintenance of the redox and energy status of the cell.
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PMID:Sugar levels modulate sorbitol dehydrogenase expression in maize. 1856 93

The logic gates NAND/NOR were mimicked by enzyme biocatalyzed reactions activated by sucrose, maltose and phosphate. The subunits performing AND/OR Boolean logic operations were designed using maltose phosphorylase and cooperative work of invertase/amyloglucosidase, respectively. Glucose produced as the output signal from the AND/OR subunits was applied as the input signal for the INVERTER gate composed of alcohol dehydrogenase, glucose oxidase, microperoxidase-11, ethanol and NAD(+), which generated the final output in the form of NADH inverting the logic signal from 0 to 1 or from 1 to 0. The final output signal was amplified by a self-promoting biocatalytic system. In order to fulfill the Boolean properties of associativity and commutativity in logic networks, the final NADH output signal was converted to the initial signals of maltose and phosphate, thus allowing assembling of the same standard units in concatenated sequences. The designed modular approach, signal amplification and conversion processes open the way toward complex logic networks composed of standard elements resembling electronic integrated circuitries.
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PMID:Enzyme-based NAND and NOR logic gates with modular design. 1990 34

Bud burst in certain species is conditioned by the luminous environment. With roses, the requirement for light is absolute, and darkness totally inhibits bud burst. Few studies have looked into understanding the action of light on the physiological bud burst processes. Here, we show the impact of light on certain components of glucidic metabolism during bud burst. Measurements were taken on decapitated plants of Rosa hybrida L. 'Radrazz' exposed either to darkness, white, blue or R light. Results show that a mobilization of bud and the carrying stem sucrose reserves only takes place in light and accompanies the bud burst. Furthermore, the activity of the RhVI vacuolar acid invertase which contributes to the breakdown of sucrose in the buds, as well as the transcription of the RhVI gene, is reduced in darkness, although it is strongly stimulated by light. The same analysis concerning the RhNAD-SDH gene, coding an NAD-dependent sorbitol dehydrogenase, shows, on the contrary, a strong induction of its transcription in darkness that could reflect the use of survival mechanisms in this condition.
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PMID:Sugars are under light control during bud burst in Rosa sp. 2037 36

1. Electron microscopic studies of the sieve tube sap obtained from the secondary phloem of Robinia pseudoacacia by the method of Hartig (1860) showed the presence of well developed mitochondria in addition to membrane fragments. 2. In this sieve tube sap the following enzymes could be detected qualitatively: UTP-glucose-1-phosphate-uridyl transferase, UDPG-fructose glucosyl transferase, glucose-6-phosphate dehydrogenase, hexokinase (for glucose and fructose), phosphohexose isomerase, phosphofructokinase, and UDPG-pyrophosphatase. 3. The following enzymes were determined quantitatively: phosphorylase, amylase, aldolase, triosephosphate isomerase, NAD(+)-dependent glyceraldehyde-3-phosphate dehydrogenase, phosphoglyceromutase, enolase, pyruvate kinase, pyruvate decarboxylase, alcohol dehydrogenase, isocitrate dehydrogenase, fumarase, malate dehydrogenase, glutamate-pyruvate transaminase, glutamate dehydrogenase, glutamate-oxalacetate transaminase, and anorganic pyrophosphatase. 4. The following enzymes could not be detected: UDGP dehydrogenase, UDPG-fructose-6-phosphate-glucosyltransferase, invertase, phosphoglucomutase, lactate dehydrogenase, and citrate synthase. 5. The enzyme pattern in the sieve tube saps of Tilia platyphyllos, Carpinus betulus, Fraxinus americana, Quercus borealis maxima, and Salix viminalis is qualitatively similar to that of Robinia, but shows quantitative differences (as far as analyzed). 6. The meaning of the results for the metabolism and function of the sieve tubes in situ is discussed.
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PMID:[Enzyme activities in the sieve tube sap of Robinia pseudoacacia L. and of other tree species]. 2449 58

Heat stress impairs both pollen germination and pollen tube elongation, resulting in pollination failure caused by energy imbalance. Invertase plays a critical role in the maintenance of energy homoeostasis; however, few studies investigated this during heat stress. Two rice cultivars with different heat tolerance, namely, TLY83 (heat tolerant) and LLY722 (heat susceptible), were subjected to heat stress. At anthesis, heat stress significantly decreased spikelet fertility, accompanied by notable reductions in pollen germination on stigma and pollen tube elongation in ovule, especially in LLY722. Acid invertase (INV), rather than sucrose synthase, contributed to sucrose metabolism, which explains the different tolerances of both cultivars. Under heat stress, larger enhancements in NAD(H), ATP, and antioxidant capacity were found in TLY83 compared with LLY722, whereas a sharp reduction in poly(ADP-ribose) polymerase (PARP) activity was found in the former compared with the latter. Importantly, exogenous INV, 3-aminobenzamide (a PARP inhibitor), sucrose, glucose, and fructose significantly increased spikelet fertility under heat stress, where INV activity was enhanced and PARP activity was inhibited. Therefore, INV can balance the energy production and consumption to provide sufficient energy for pollen germination and pollen tube growth under heat stress.
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PMID:Acid invertase confers heat tolerance in rice plants by maintaining energy homoeostasis of spikelets. 3199 45


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