Predicting in-vivo digestibilities of herbages by exhaustive enzymic hydrolysis of cell walls

1977 ◽  
Vol 28 (12) ◽  
pp. 1057-1064 ◽  
Author(s):  
P. Grattan Roughan ◽  
Ross Holland
Keyword(s):  
Cell Walls ◽  
Enzymic Hydrolysis ◽  
Hydrolysis Of

Enzymic Hydrolysis of Stilbestrol Diphosphate in vitro and in vivo.

1961 ◽  
Vol 106 (2) ◽  
pp. 327-330 ◽  
Author(s):  
W. Johnson ◽  
R. Jasmin ◽  
G. Corte
Keyword(s):  
Enzymic Hydrolysis ◽  
Hydrolysis Of

scholarly journals SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO

1932 ◽  
Vol 15 (5) ◽  
pp. 491-495 ◽  
Author(s):  
J. M. Nelson ◽  
Elizabeth T. Palmer ◽  
B. G. Wilkes
Keyword(s):  
Yeast Cells ◽  
Enzymic Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Live Yeast

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.

scholarly journals Double labeling with [3H]thymidine and [125I]iododeoxyuridine as a method for determining the fate of injected DNA and cells in vivo.

1975 ◽  
Vol 67 (2) ◽  
pp. 484-488 ◽  
Author(s):  
D K Myers ◽  
L E Feinendegen
Keyword(s):  
T Cells ◽  
Human Kidney ◽  
Enzymic Hydrolysis ◽  
Double Labeling ◽  
Exogenous Dna ◽  
Mouse Thymus ◽  
Whole Cells ◽  
Thymus Cells ◽  
Hydrolysis Of

Mice were injected intravenously and intraperitoneally with preparations of intestinal nucleoprotein, spleen nuclei, mouse thymus cells, or human kidney T cells whose DNA had been labeled with both [3H]thymidine (TdR) and [125I]-iododeoxyuridine (IUdR). Since free TdR is reutilized more efficiently than free IUdR produced by enzymic hydrolysis of the exogenous DNA, the ratio of [3H]TdR/[125I]IUdR in the DNA fraction of the tissues of the recipient mice provides a measure of the amount of intact exogenous DNA in the tissue. In most instances, the doubly labeled exogenous DNA was almost completely hydrolyzed within 1 day injection, but survival of the DNA from whole cells could be demonstrated in some cases.

Structure and composition of the alkali-insoluble cell wall fraction of Coprinus macrorhizus var. microsporus

1980 ◽  
Vol 58 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Carey B. Bottom ◽  
Donald J. Siehr
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Acid Hydrolysis ◽  
Cell Walls ◽  
Cell Wall Fraction ◽  
Enzymic Hydrolysis ◽  
Methylation Analysis ◽  
Partial Acid Hydrolysis ◽  
The Core ◽  
Hydrolysis Of

The alkali-insoluble (R-) fraction from the cell walls of Coprinus macrorhizus var. microsporus is a highly branched glucan, containing α-(1 → 4), β-(1 → 3), and β-(1 → 6) linkages as shown by methylation, partial acid hydrolysis, and enzymic hydrolysis. The α-(1 → 4)-linked segments are joined by occasional β-(1 → 3) links as suggested by the identification of 2-O-α-glucopyranosyl erythritol in the hydrolysate of the reduced, periodate-oxidized glucan. Hydrolysis of the permethylated glucan gave nearly equimolar amounts of 2,4-di- and 2,3-di-O-methyl-D-glucose. Methylation analysis of the residue from enzymic hydrolysis, the "CORE-fraction," indicated the presence of glucose residues in this fraction linked through positions O1, O3, O4, and O6. Hydrolysates of the R-fraction contained mannose, glucosamine, and amino acids in addition to glucose.

Enzymic hydrolysis of diferulates from wheat bran cell walls

1998 ◽  
Vol 26 (2) ◽  
pp. S168-S168 ◽  
Author(s):  
Maria T. Garcia-Conesa ◽  
Paul A. Kroon ◽  
Gary Williamson
Keyword(s):  
Wheat Bran ◽  
Cell Walls ◽  
Enzymic Hydrolysis ◽  
Hydrolysis Of

Studies on the mechanism of acute inhibition of thyroglobulin hydrolysis by iodine

1985 ◽  
Vol 108 (4) ◽  
pp. 511-517 ◽  
Author(s):  
Nandalal Bagchi ◽  
Birdie Shivers ◽  
Thomas R. Brown
Keyword(s):  
Time Course ◽  
Period 2 ◽  
Iodotyrosine Deiodinase ◽  
Rate Of Hydrolysis ◽  
Underlying Mechanisms ◽  
Excess Iodide ◽  
Sites Of Action ◽  
Hydrolysis Of

Abstract. Iodine in excess is known to acutely inhibit thyroidal secretion. In the present study we have characterized the time course of the iodine effect in vitro and investigated the underlying mechanisms. Labelled thyroid glands were cultured in vitro in medium containing mononitrotyrosine, an inhibitor of iodotyrosine deiodinase. The rate of hydrolysis of labelled thyroglobulin was measured as the proportion of labelled iodotyrosines and iodothyronines recovered at the end of culture and was used as an index of thyroidal secretion. Thyrotrophin (TSH) administered in vivo acutely stimulated the rate of thyroglobulin hydrolysis. Addition of Nal to the culture medium acutely inhibited both basal and TSH-stimulated thyroglobulin hydrolysis. The effect of iodide was demonstrable after 2 h, maximal after 6 h and was not reversible upon removal of iodide. Iodide abolished the dibutyryl cAMP induced stimulation of thyroglobulin hydrolysis. Iodide required organic binding of iodine for its effect but new protein or RNA synthesis was not necessary. The inhibitory effects of iodide and lysosomotrophic agents such as NH4C1 and chloroquin on thyroglobulin hydrolysis were additive suggesting different sites of action. Iodide added in vitro altered the distribution of label in prelabelled thyroglobulin in a way that suggested increased coupling in the thyroglobulin molecule. These data indicate that 1) the iodide effect occurs progressively over a 6 h period, 2) continued presence of iodide is not necessary once the inhibition is established, 3) iodide exerts its action primarily at a post cAMP, prelysosomal site and 4) the effect requires organic binding of iodine, but not new RNA or protein synthesis. Our data are consistent with the hypothesis that excess iodide acutely inhibits thyroglobulin hydrolysis by increasing the resistance of thyroglobulin to proteolytic degradation through increased iodination and coupling.

scholarly journals Optimized 5-Fluorouridine Prodrug for Co-Loading with Doxorubicin in Clinically Relevant Liposomes

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 107
Author(s):  
Debra Wu ◽  
Douglas Vogus ◽  
Vinu Krishnan ◽  
Marta Broto ◽  
Anusha Pusuluri ◽  
...  
Keyword(s):  
Single Agent ◽  
Molar Ratio ◽  
Control Group ◽  
Drug Tolerability ◽  
Breast Cancer Model ◽  
In Vivo Testing ◽  
Chemical Profiles ◽  
Hydrolysis Of ◽  
Doxorubicin Liposomes

Liposome-based drug delivery systems have allowed for better drug tolerability and longer circulation times but are often optimized for a single agent due to the inherent difficulty of co-encapsulating two drugs with differing chemical profiles. Here, we design and test a prodrug based on a ribosylated nucleoside form of 5-fluorouracil, 5-fluorouridine (5FUR), with the final purpose of co-encapsulation with doxorubicin (DOX) in liposomes. To improve the loading of 5FUR, we developed two 5FUR prodrugs that involved the conjugation of either one or three moieties of tryptophan (W) known respectively as, 5FUR−W and 5FUR−W3. 5FUR−W demonstrated greater chemical stability than 5FUR−W3 and allowed for improved loading with fewer possible byproducts from tryptophan hydrolysis. Varied drug ratios of 5FUR−W: DOX were encapsulated for in vivo testing in the highly aggressive 4T1 murine breast cancer model. A liposomal molar ratio of 2.5 5FUR−W: DOX achieved a 62.6% reduction in tumor size compared to the untreated control group and a 33% reduction compared to clinical doxorubicin liposomes in a proof-of-concept study to demonstrate the viability of the co-encapsulated liposomes. We believe that the new prodrug 5FUR−W demonstrates a prodrug design with clinical translatability by reducing the number of byproducts produced by the hydrolysis of tryptophan, while also allowing for loading flexibility.

scholarly journals Catalytic activity and stereoselectivity of engineered phosphotriesterases towards structurally different nerve agents in vitro

2021 ◽  
Author(s):  
Anja Köhler ◽  
Benjamin Escher ◽  
Laura Job ◽  
Marianne Koller ◽  
Horst Thiermann ◽  
...  
Keyword(s):  
Plasma Clearance ◽  
Nerve Agents ◽  
Inhibition Assay ◽  
Ache Inhibition ◽  
Catalytic Activities ◽  
Chiral Lc ◽  
Hydrolysis Of ◽  
Medical Countermeasures

AbstractHighly toxic organophosphorus nerve agents, especially the extremely stable and persistent V-type agents such as VX, still pose a threat to the human population and require effective medical countermeasures. Engineered mutants of the Brevundimonas diminuta phosphotriesterase (BdPTE) exhibit enhanced catalytic activities and have demonstrated detoxification in animal models, however, substrate specificity and fast plasma clearance limit their medical applicability. To allow better assessment of their substrate profiles, we have thoroughly investigated the catalytic efficacies of five BdPTE mutants with 17 different nerve agents using an AChE inhibition assay. In addition, we studied one BdPTE version that was fused with structurally disordered PAS polypeptides to enable delayed plasma clearance and one bispecific BdPTE with broadened substrate spectrum composed of two functionally distinct subunits connected by a PAS linker. Measured kcat/KM values were as high as 6.5 and 1.5 × 108 M−1 min−1 with G- and V-agents, respectively. Furthermore, the stereoselective degradation of VX enantiomers by the PASylated BdPTE-4 and the bispecific BdPTE-7 were investigated by chiral LC–MS/MS, resulting in a several fold faster hydrolysis of the more toxic P(−) VX stereoisomer compared to P(+) VX. In conclusion, the newly developed enzymes BdPTE-4 and BdPTE-7 have shown high catalytic efficacy towards structurally different nerve agents and stereoselectivity towards the toxic P(−) VX enantiomer in vitro and offer promise for use as bioscavengers in vivo.

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