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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)

We report here on the molecular nature of an EMS-induced mutant, mn1-89, a leaky semidominant allele of the Miniature1 (Mn1) seed locus that encodes a seed-specific cell wall invertase, INCW2. The mn1-89 locus specifies normal levels of the Incw2 transcript but extremely low levels (about 6% of normal) of the protein and enzyme activity are expressed. Sequence analysis of Incw2 clones derived from the parental Mn1 and the mutant genotypes shows a C to T transition in the mn1-89 allele, leading to a single amino acid alteration (proline to leucine) near the C-terminus of the mutant INCW2 protein. Although this change is not in the catalytic domain, putative N-glycosylation sites, or the beta-fructosidase motif, it does lie in a motif that is well conserved among all plant invertases and related fructosyltransferases. On the basis of these genetic in planta data, we believe we have identified a proline residue in a hitherto unknown GPFG motif as critical for the stability of such proteins. The single base change (C to T) also leads to the elimination of a BglI restriction site in the mutant allele. Indeed, BglI restriction digests of genomic DNAs from mn1-89 and Mn1 genotypes show one and two fragments, respectively. Sequence analysis of RT-PCR-derived endosperm Incw clones from mn1-1 (the reference allele) seeds predict five amino acid substitutions relative to Mn1. Whether or not these sequences are encoded by the mn1-1 locus or another non-allelic Incw gene in the maize genome remains to be elucidated.
Mol Gen Genet 2000 Mar
PMID:A point mutation at the Miniature1 seed locus reduces levels of the encoded protein, but not its mRNA, in maize. 1077 57

This article reviews most of the author's studies on process development and reactor design for continuous microbial reactions. (1) Enzyme reactions of growing and non-growing microbial cells immobilized in agar gel beads were analyzed pertaining to the effects of external and internal diffusion of substrate on reaction kinetics. (2) Experimental correlations of production rates of beta-fructosidase and acid phosphatase with dilution rate of continuous culture were simulated based on an operon model for enzyme regulation. (3) Population dynamics of an amylase-producing bacteria and their mutant were discussed in relation to enzyme productivity in a continuous culture of spore-forming bacteria. (4) Plasmid mobilization in a mixed population of donor, recipient, and helper cells was investigated in a continuous culture as a model study of accidental release of a genetically modified plasmid into a natural environment. (5) A production rate increase of up to 100-fold was achieved by cell-recycle culturing of continuous acetic acid fermentation using a filter module with a hollow fiber membrane. (6) The feasibility of a continuous surface culture for the biooxidation of organic substances was ascribed to an enhanced oxygen absorption rate in the presence of a microbial film on a liquid surface. (7) Simultaneous separation of inhibitory products using an electrodialysis module during some organic acid fermentations was effective for increasing production in a continuous culture.
J Gen Appl Microbiol 2003 Aug
PMID:Theoretical and methodological studies of continuous microbial bioreactors. 1458 91

Overexpression of the rntA cDNA encoding RNase T1 derived from A. oryzae causes severe growth inhibition in S. cerevisiae. We previously reported that most S. cerevisiae mutant strains defective in translocation into the ER, ER-Golgi transport and vacuole formation exhibited hypersensitivity to expression of RNase T1. Screening for S. cerevisiae mutants that showed RNase T1 hypersensitivity resulted in the isolation of 38 (rns) mutant strains. Some of these mutants showed a variety of phenotypes including temperature-sensitive growth, hypersensitivity to G418, defect in invertase glycosylation and fragmented vacuoles. We identified the genes mutated in three of the rns mutants, rns1, rns2, and rns3, as DSL1, UMP1, and SEC17, respectively. Fluorescence microscopic observation showed that GFP or myc-tagged Rns1p was localized at the nuclear region in the cell. Two-hybrid screening revealed the interaction of Rns1p with a transcription factor Cin5p and a functionally unknown Ylr440cp. It was observed that HA-tagged Ylr440cp was localized to the ER and nuclear envelope.
J Gen Appl Microbiol 2005 Apr
PMID:Isolation of Saccharomyces cerevisiae RNase T1 hypersensitive (rns) mutants and genetic analysis of the RNS1/DSL1 gene. 1594 68

The saccharogenic enzymes present in potato juice were studied. The actions were followed upon the substances present in the juice and upon added sucrose, maltose, and soluble starch. Sucrase and amylase were found to be present in the juice. No indication of a maltase was obtained. The sucrase showed optimum conditions for action at pH 4 to 5, the amylase at pH 6 to 7, both upon the starch present in the juice and upon added soluble starch. The action of a yeast sucrase preparation upon the juice showed the presence of sucrose (or raffinose) in a concentration of the order of magnitude of 1 per cent.
J Gen Physiol 1920 Jan 20
PMID:STUDIES ON ENZYME ACTION : XVIII. THE SACCHAROGENIC ACTIONS OF POTATO JUICE. 1987 4

In Echinodontium tinctorium the presence of the following enzymes was demonstrated: esterase, maltase, lactase, sucrase, raffinase, diastase, inulase, cellulase, hemicellulase, urease, rennet, and catalase.
J Gen Physiol 1920 Jul 20
PMID:ENZYME ACTION IN ECHINODONTIUM TINCTORIUM ELLIS AND EVERHART. 1987 34

A number of different methods of treatment of unripe and ripe bananas for the purpose of obtaining and studying sucrolytic and amylolytic enzymes are described. No conclusive evidence of the presence of an amlyase could be obtained in any of the preparations. The sucrase of unripe and ripe bananas was studied more extensively. With ripe bananas, both soluble and insoluble sucrase preparations were obtained. Conditions for converting the soluble into an insoluble form were found. The actions of the sucrase preparations as far as the hydrogen ion concentration for maximum action and the time-action relation are concerned are similar to the behavior of the yeast and the potato sucrase.
J Gen Physiol 1921 May 20
PMID:STUDIES ON ENZYME ACTION : XIX. THE SUCROLYTIC ACTIONS OF BANANAS. 1987 90

Circumstantial evidence is presented which indicates that Polyporus volvatus is parasitic. Cultures of Polyporus volvatus and Fomes igniarius may be obtained from the young sporophores by the tissue method. In Polyporus volvatus the presence of the following enzymes was demonstrated: esterase, maltase, lactase, sucrase, raffinase, diastase, inulase, cellulase, hemicellulase, glucosidase, rennet, and catalase. In Fomes igniarius the presence of the following enzymes was demonstrated: esterase, maltase, lactase, sucrase, raffinase, diastase, inulase, cellulase, hemicellulase, glucosidase, urease, rennet, and catalase.
J Gen Physiol 1921 Jul 20
PMID:STUDIES IN WOOD DECAY : II. ENZYME ACTION IN POLYPORUS VOLVATUS PECK AND FOMES IGNIARIUS (L.) GILLET. 1987 5

The radiochemical inactivation of invertase by beta radiation from the radioactive products in equilibrium with radium emanation can be explained quantitatively on the same basis as that of trypsin and pepsin previously reported; namely, the rate of change in the logarithm of the concentration of the active enzyme with respect to the variable, W, is constant, under the conditions of irradiation described, when the volume of solution exposed is constant. When, within the limits stated in this paper, this volume (V) is varied, the rate of radiochemical change is inversely proportional to V; i.e., See PDF for Equation.
J Gen Physiol 1925 Nov 20
PMID:THE EFFECT OF RADIOACTIVE RADIATIONS AND X-RAYS ON ENZYMES : IV. THE EFFECT OF RADIATIONS FROM RADIUM EMANATION ON SOLUTIONS OF INVERTASE. 1987 45

1. Considering previously published data on the velocity of hydrolysis of glucosides by acids, it is shown that phloridzin, judged from the standpoint of the velocity coefficient and the critical increment for hydrolysis, resembles the gamma-fructosides (sucrose, raffinose and melezitose) more closely than it does the normal glucosides (salicin, arbutin, maltose, etc.). 2. Previous work on the enzymic hydrolysis of phloridzin shows that it is not hydrolysed by emulsin, but that it is hydrolysed by some other enzyme which occurs fairly freely in nature. 3. The difficulty in examining the enzymic hydrolysis of phloridzin lies in its very low solubility. It has been shown, in confirmation of earlier work, that emulsin is definitely without action on phloridzin at various values of pH and of temperature. This result is difficult to reconcile with the beta-glucosidic character commonly ascribed to phloridzin, and with the fact that emulsin hydrolyses (synthetic) phloroglucinol-beta-glucoside, of which phlorizin is regarded as a derivative. 4. Phloridzin is hydrolysed by a yeast maltase preparation, known to contain saccharase. Phloridzin is readily attacked by maltase-free saccharase at 30 degrees C. and pH of 4.45. If the alpha-glucase of the sucrose-splitting enzyme is (as stated) inactive under these conditions, then the enzyme responsible for the hydrolysis of phloridzin is beta-(gamma) fructosidase. 5. The sugar prepared from phloridzin differs from glucose in its specific rotation and in its action towards Bacillus pestis.
J Gen Physiol 1930 Jul 20
PMID:THE ENZYMIC HYDROLYSIS OF PHLORIDZIN. 1987 65

1. A method is given whereby the course of hydrolysis of sucrose by live yeast cells may be followed with precision equal to that found when invertase solutions prepared from autolyzed yeast are used to cause inversion. 2. The practical value of the equation of Nelson and Hitchcock as a means of following the course of enzymic hydrolysis of sucrose is hereby extended. 3. The inversion of sucrose by live yeast cells and by extracted invertase has been quantitatively compared. 4. The course of hydrolysis of sucrose by the invertase of Fleischmann's yeast has been found to be identical in vivo and in vitro.
J Gen Physiol 1932 May 20
PMID:SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO. 1987 60


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