Hydrolytic Proteins of Sugarcane: The Acid Invertases

1969 ◽  
Vol 49 (3) ◽  
pp. 287-307
Author(s):  
Alex G. Alexander
Keyword(s):  
Substrate Concentration ◽  
Fine Powder ◽  
Invertase Activity ◽  
Leaf Sheath ◽  
Acid Invertase ◽  
Inhibitory Effects ◽  
Yeast Invertase ◽  
Optimum Ph ◽  
High Concentrations ◽  
Polysaccharide Hydrolysis

Invertase has been extracted from meristem, leaf, sheath, node, and internode tissue of sugarcane. The meristem was the richest source for invertase acting under both acidic (pH 4.65) and neutral (pH 7.0) conditions. Acid invertase was extracted from meristem with water after the samples had been frozen, lyophilized, ground to a fine powder, and sonified in a powder-water suspension. Virtually all invertase was precipitated from solution with ammonium sulfate below 55-percent saturation. Acid invertase was precipitated primarily between 30- and 52-percent saturation. Within the acid-invertase preparation, two distinct enzymes were demonstrated, one, α-glucosidase, "taka-invertase", which attacks the glucose end of the sucrose molecule, and the other, ß-fructosidase, "yeast invertase", attacking the fructose end. ß-fructosidase is predominant by about 2 to 1. The possibility that α-glucosidase takes part in the degradation of glucosidically linked oligosaccharides, or products of polysaccharide hydrolysis, is discussed. Optimum pH for the acid-invertase preparation lay between 4.75 and 5.5. Optimum temperature was 44° C, and substrate concentration about 80 µmoles of sucrose per milliliter of digest. Invertase was inhibited by iodide, lead, and mercury at concentrations of 1.0, 0.5, and 0.0003 µmole/ml. of digest, respectively. Iodide inhibition was completely reversed by increasing substrate concentration, and lead inhibition was partly reversed. The inhibitory effects of mercury were not reversible. Arsenic and tungsten also inhibited invertase, but at relatively high concentrations, 5.0 and 10.0 µmoles/ml. of digest, respectively. Manganese doubled invertase activity at 0.5 µmole/ml. of digest, and as little as 0.005 µmole markedly stimulated the reaction. Prolonged dialysis (36 hours) against distilled water reduced invertase activity by about 95 percent. Added manganese revived the activity and stimulated the enzyme beyond predialysis levels. Activity was also revived by sucrose, maltose, galactose, glucose, and fructose, when these were added to the dialyzed enzyme. It was concluded that the active, acid-invertases are protein-sugar-manganese complexes, in which the protein constituent is virtually inactive in the absence of either manganese or sugar.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

744 PB 076 IDENTIFICATION OF BOTH ACID AND NEUTRAL INVERTASE ACTIVITY IN DEVELOPING STRAWBERRY FRUIT

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 539f-539
Author(s):  
Kirk W. Pomper ◽  
Patrick J. Breen
Keyword(s):  
Extraction Procedure ◽  
Invertase Activity ◽  
Assimilate Transport ◽  
Strawberry Fruit ◽  
Fruit Extracts ◽  
Neutral Invertase ◽  
Optimum Ph ◽  
Cold Acetone ◽  
Ripe Stage ◽  
Sugar Levels

Invertase (INV) may influence sugar levels and assimilate transport in strawberry fruit. Several groups, including our own, have only detected acid INV (optimum pH 4.6) in strawberry fruit, however, recently Hubbard et al. (Physiol. Plant. 82:191-196, 1991) reported the presence of a neutral INV (pH 7.5). Since dissimilar isolation protocols may have contributed to the different findings, we re-examined our work with developing `Brighton' strawberry using the extraction procedure of Hubbard et al. Neutral INV activity per gFW (pH 7.5-8.0) increased many fold as fruit developed from green to the red ripe stage. Acid INV activity decreased markedly from green-white to the red stage. In addition, when fruit extracts were precipitated with cold acetone, a pellet contained 60% of the acid INV activity, and a surface coagulation of protein contained 60% of the neutral INV activity. This allowed easy separation of these two enzymes. Extraction methodologies affect isolation of neutral INV activity from strawberry fruit.

Alkaline phosphatase. I. Kinetics and inhibition by levamisole of purified isoenzymes from humans.

1976 ◽  
Vol 22 (7) ◽  
pp. 972-976 ◽  
Author(s):  
H Van Belle
Keyword(s):  
Alkaline Phosphatase ◽  
Substrate Concentration ◽  
Human Liver ◽  
Alkaline Phosphatases ◽  
Mechanism Of Inhibition ◽  
Optimum Ph ◽  
Alkaline Phosphatase Isoenzymes

Abstract I studied the kinetics and sensitivity toward inhibition by levamisole and R 8231 of the most important human alkaline phosphatase isoenzymes. N-Ethylaminoethanol proved superior to the now widely used diethanolamine buffer, especially for the enzymes from the intestine and placenta, behaving as an uncompetitive activator. The optimum pH largely depends on the substrate concentration. The addition of Mg2+ has no effect on the activities. The meaning of Km-values for alkaline phosphatases is questioned. Isoenzymes from human liver, bone, kidney, and spleen are strongly inhibited by levamisole or R 8231 at concentrations that barely affect the enzymes from intestine or placenta. The inhibition is stereospecific, uncompetitive, and not changed by Mg2+. Inhibition is counteracted by increasing concentrations of N-ethylaminoethanol. The mechanism of inhibition is suggested to be formation of a complex with the phosphoenzyme.

A simulated mucus layer protects Lactobacillus reuteri from the inhibitory effects of linoleic acid

2013 ◽  
Vol 4 (4) ◽  
pp. 299-312 ◽  
Author(s):  
R. De Weirdt ◽  
E. Coenen ◽  
B. Vlaeminck ◽  
V. Fievez ◽  
P. Van den Abbeele ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Lactobacillus Reuteri ◽  
Close Contact ◽  
Mucus Layer ◽  
Inhibitory Effects ◽  
Intestinal Mucus ◽  
Gut Microbe ◽  
Protective Environment ◽  
Bacterial Cell Membrane ◽  
High Concentrations

Lactobacillus reuteri is a commensal, beneficial gut microbe that colonises the intestinal mucus layer, where it makes close contact with the human host and may significantly affect human health. Here, we investigated the capacity of linoleic acid (LA), the most common polyunsaturated fatty acid (PUFA) in a Western-style diet, to affect L. reuteri ATCC PTA 6475 prevalence and survival in a simulated mucus layer. Short-term (1 h) survival and mucin-agar adhesion assays of a log-phase L. reuteri suspension in intestinal water demonstrated that the simulated mucus layer protected L. reuteri against the inhibitory effects of LA by lowering its contact with the bacterial cell membrane. The protective effect of the simulated mucus layer was further evaluated using a more complex and dynamic model of the colon microbiota (SHIME®), in which L. reuteri survival was monitored during 6 days of daily exposure to LA in the absence (L-SHIME) and presence (M-SHIME) of a simulated mucus layer. After 6 days, luminal L- and M-SHIME L. reuteri plate counts had decreased by 3.1±0.5 and 2.6±0.9 log cfu/ml, respectively. Upon supplementation of 1.0 g/l LA, the decline in the luminal L. reuteri population started earlier than was observed for the control. In contrast, mucin-agar levels of L. reuteri (in the M-SHIME) remained unaffected throughout the experiment even in the presence of high concentrations of LA. Overall, the results of this study indicate the importance of the mucus layer as a protective environment for beneficial gut microbes to escape from stress by high loads of the antimicrobial PUFA LA to the colon, i.e. due to a Western-style diet.

β-GLUCURONIDASE OF RABBIT POLYMORPHONUCLEAR LEUCOCYTES

1950 ◽  
Vol 28e (3) ◽  
pp. 69-79 ◽  
Author(s):  
R. J. Rossiter ◽  
Esther Wong
Keyword(s):  
Enzyme Activity ◽  
Blood Plasma ◽  
Substrate Concentration ◽  
Final Concentration ◽  
White Cell ◽  
Polymorphonuclear Leucocytes ◽  
Michaelis Constant ◽  
Glucuronidase Activity ◽  
Arsanilic Acid ◽  
Optimum Ph

Rabbit polymorphonuclear leucocytes contain an enzyme capable of hydrolyzing biosynthetic phenolphthalein mono-β-glucuronide. The concentration of the enzyme in the white cell is some 2000 times the concentration of the enzyme in the blood plasma. Under the conditions of study, the β-glucuronidase activity was proportional to the concentration of the enzyme. The effect of substrate concentration on the enzyme activity was studied and the Michaelis constant, Ks, determined. The course of the reaction was linear with time for the first 12 hr. and then fell off slightly during the next 12 hr. The optimum pH of the enzyme was 4.45 in either 0.2 M acetate or 0.2 M phthalate buffer. It was not inhibited by cyanide, azide, iodoacetate, fluoride, glycine, thiourea, urethane, arsanilic acid, acetophenone, o-cresol or m-cresol, in a final concentration of 0.01 M. The possible function of β-glucuronidase in rabbit polymorphonuclear leucocytes is discussed.

The assay and partial characterization of 3β-hydroxysteroid sulfotransferase of the hamster epididymis

1985 ◽  
Vol 63 (1) ◽  
pp. 71-76 ◽  
Author(s):  
M. Bouthillier ◽  
G. Bleau ◽  
A. Chapdelaine ◽  
K. D. Roberts
Keyword(s):  
Organic Phase ◽  
Enzyme Preparation ◽  
Enzymatic Reaction ◽  
Partial Characterization ◽  
Optimal Conditions ◽  
Steroid Nucleus ◽  
Optimum Ph ◽  
High Concentrations

Using a partially purified enzyme preparation obtained from hamster epididymis, a simple assay has been developed to measure the sulfurylation of dehydroisoandrosterone (DHA) and desmosterol in the presence of 3′-phosphoadenosine 5′-phospho[35S]sulfate ([35S]PAPS). After stopping the enzymatic reaction with methanol and KCl, the 35S-labelled steroid sulfates are readily extracted into an organic phase. Optimal conditions for the sulfurylation of the two steroids were compared; optimum pH is 8.7 for DHA and 9.8 for desmosterol. Sulfoconjugation of desmosterol increases with magnesium concentrations up to 6 mM, while 40 mM concentrations of the divalent ion are required for the optimal sulfurylation of DHA. Maximum sulfurylation of these steroids requires the presence of 15 mM cysteine. Michaelis–Menten kinetics are observed with DHA which has an apparent Km of 32 μM, while desmosterol inhibits sulfotransferase activity at high concentrations. Saturation of the enzyme with PAPS results in an allosteric behaviour. Only the 3β-hydroxyl function of the steroid nucleus appears to be an appropriate sulfate acceptor for the epididymal hydroxysteroid sulfotransferase.

RELATIONSHIP BETWEEN ACID INVERTASE ACTIVITY AND SUGAR CONTENT IN GRAPE SPECIES

2011 ◽  
Vol 35 (6) ◽  
pp. 1646-1652 ◽  
Author(s):  
DEVAIAH KAMBIRANDA ◽  
HEMANTH VASANTHAIAH ◽  
SHEIKH M. BASHA
Keyword(s):  
Sugar Content ◽  
Invertase Activity ◽  
Acid Invertase

Autotoxic compounds from rhizosphere soil of lanzhou lily extracts: Identification and biological activity

2021 ◽  
Vol 53 (1) ◽  
pp. 111-126
Author(s):  
Y. F. Huang ◽  
E. H. Zhang ◽  
X. H. Zhang ◽  
Q. Wang ◽  
H. Z. Wang ◽  
...  
Keyword(s):  
Antioxidant Enzyme ◽  
Seedling Growth ◽  
Rhizosphere Soil ◽  
Gas Chromatography Mass Spectrometry ◽  
Antioxidant Enzyme Activities ◽  
Photosynthetic Parameters ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
High Concentrations ◽  
Lanzhou Lily

We investigated the autotoxicity of Lanzhou lily rhizosphere soil with different cultivation years. The allelochemicals in such soils were isolated and identified by gas chromatography-mass spectrometry (GC-MS). Based on our earlier studies, the antioxidant 2246 and dioctyl terephthalate were found in lily sick soil were used in pot experiments determine to their autotoxic effects on the Lanzhou lily seedlings growth, photosynthetic parameters and antioxidant enzyme activities in seedling leaves. The content of antioxidant 2246 and dioctyl terephthalate was determined by GC-MS in rhizosphere soil of different cultivation years. The aqueous extracts of Lanzhou lily rhizosphere soil promoted the growth of its own seedlings at 0.2 mg·mL-1, however, the concentrations > 2 mg·mL-1 were inhibitory. The longer the cultivation period (1-yr, 2-yr and 4-yr), the stronger were the inhibitory effects. In rhizosphere soils of 1-yr, 2-yr and 4-yr ; 8,: 15 and 18 compounds were identified, respectively. The identified compounds were camphor, 3-hydroxy-4-methoxy-benzaldehyde, 2,4-bis(1,1- dimethylethyl)-phenol, tributyl phosphate, dibutyl phthalate, antioxidant 2246 and dioctyl terephthalater and these are reported as allelochemicals. The pot experiment results showed that low concentrations of antioxidant 2246 stimulated the seedling growth but high concentrations were inhibitory, while all concentrations of dioctyl terephthalater inhibited the seedling growth. At 100 mg·mL-1, the antioxidant 2246 and dioctyl terephthalate significantly inhibited the photosynthesis and antioxidant enzyme activity in leaves (P <0.05). Furthermore, the content of these two compounds in soils increased with the increase of cultivation years. These results suggested that allelochemicals accumulated in replanted soil contributed to the autotoxicity of Lanzhou lily in rhizosphere soil.

scholarly journals The Tolerance of Salinity in Rice Requires the Presence of a Functional Copy of FLN2

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
Guang Chen ◽  
Jiang Hu ◽  
Liuliu Dong ◽  
Dali Zeng ◽  
Longbiao Guo ◽  
...  
Keyword(s):  
Salinity Stress ◽  
Salinity Tolerance ◽  
Sugar Metabolism ◽  
Invertase Activity ◽  
Leaf Sheath ◽  
Japonica Rice ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Genes Encoding ◽  
Knockout Line

A panel of ethane-methyl-sulfonate-mutagenized japonica rice lines was grown in the presence of salinity in order to identify genes required for the expression of salinity tolerance. A highly nontolerant selection proved to harbor a mutation in FLN2, a gene which encodes fructokinase-like protein2. Exposure of wild-type rice to salinity up-regulated FLN2, while a CRISPR/Cas9-generated FLN2 knockout line was hypersensitive to the stress. Both ribulose 1,5-bisphosphate carboxylase/oxygenase activity and the abundance of the transcript generated by a number of genes encoding components of sucrose synthesis were lower in the knockout line than in wild-type plants’ leaves, while the sucrose contents of the leaf and root were, respectively, markedly increased and decreased. That sugar partitioning to the roots was impaired in FLN2 knockout plants was confirmed by the observation that several genes involved in carbon transport were down-regulated in both the leaf and in the leaf sheath. The levels of sucrose synthase, acid invertase, and neutral invertase activity were distinctly lower in the knockout plants’ roots than in those of wild-type plants, particularly when the plants were exposed to salinity stress. The compromised salinity tolerance exhibited by the FLN2 knockout plants was likely a consequence of an inadequate supply of the assimilate required to support growth, a problem which was rectifiable by providing an exogenous supply of sucrose. The conclusion was that FLN2, on account of its influence over sugar metabolism, is important in the context of seedling growth and the rice plant’s response to salinity stress.

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