Why does mutation of Gln61 in Ras by the nitro analog NGln maintain activity of Ras-GAP in hydrolysis of guanosine triphosphate?

2015 ◽  
Vol 83 (11) ◽  
pp. 2091-2099 ◽  
Author(s):  
Maria G. Khrenova ◽  
Bella L. Grigorenko ◽  
Vladimir A. Mironov ◽  
Alexander V. Nemukhin
Keyword(s):  
Guanosine Triphosphate ◽  
Hydrolysis Of

QM/MM modeling the Ras-GAP catalyzed hydrolysis of guanosine triphosphate

2005 ◽  
Vol 60 (3) ◽  
pp. 495-503 ◽  
Author(s):  
Bella L. Grigorenko ◽  
Alexander V. Nemukhin ◽  
Igor A. Topol ◽  
Raul E. Cachau ◽  
Stanley K. Burt
Keyword(s):  
Guanosine Triphosphate ◽  
Hydrolysis Of

scholarly journals Hydrolysis of Guanosine Triphosphate (GTP) by the Ras·GAP Protein Complex: Reaction Mechanism and Kinetic Scheme

2015 ◽  
Vol 119 (40) ◽  
pp. 12838-12845 ◽  
Author(s):  
Maria G. Khrenova ◽  
Bella L. Grigorenko ◽  
Anatoly B. Kolomeisky ◽  
Alexander V. Nemukhin
Keyword(s):  
Reaction Mechanism ◽  
Protein Complex ◽  
Kinetic Scheme ◽  
Complex Reaction ◽  
Guanosine Triphosphate ◽  
Hydrolysis Of

Simulated 18O kinetic isotope effects in enzymatic hydrolysis of guanosine triphosphate

2009 ◽  
Vol 74 (9) ◽  
pp. 1044-1048 ◽  
Author(s):  
A. V. Nemukhin ◽  
M. S. Shadrina ◽  
B. L. Grigorenko ◽  
X. Du
Keyword(s):  
Enzymatic Hydrolysis ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Guanosine Triphosphate ◽  
Kinetic Isotope ◽  
Hydrolysis Of

scholarly journals Alternative glycosylation controls endoplasmic reticulum dynamics and tubular extension in mammalian cells

2021 ◽  
Vol 7 (19) ◽  
pp. eabe8349
Author(s):  
Despoina Kerselidou ◽  
Bushra Saeed Dohai ◽  
David R. Nelson ◽  
Sarah Daakour ◽  
Nicolas De Cock ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Secretion ◽  
Posttranslational Modifications ◽  
Mammalian Cells ◽  
Cell Enlargement ◽  
Guanosine Triphosphate ◽  
Superresolution Imaging ◽  
Functional Aspects ◽  
The Impact ◽  
Hydrolysis Of

The endoplasmic reticulum (ER) is a central eukaryotic organelle with a tubular network made of hairpin proteins linked by hydrolysis of guanosine triphosphate nucleotides. Among posttranslational modifications initiated at the ER level, glycosylation is the most common reaction. However, our understanding of the impact of glycosylation on the ER structure remains unclear. Here, we show that exostosin-1 (EXT1) glycosyltransferase, an enzyme involved in N-glycosylation, is a key regulator of ER morphology and dynamics. We have integrated multiomics and superresolution imaging to characterize the broad effect of EXT1 inactivation, including the ER shape-dynamics-function relationships in mammalian cells. We have observed that inactivating EXT1 induces cell enlargement and enhances metabolic switches such as protein secretion. In particular, suppressing EXT1 in mouse thymocytes causes developmental dysfunctions associated with the ER network extension. Last, our data illuminate the physical and functional aspects of the ER proteome-glycome-lipidome structure axis, with implications in biotechnology and medicine.

The enthalpy changes upon hydrolysis of guanosine triphosphate anhydride and ester bonds

1981 ◽  
Vol 212 (1) ◽  
pp. 72-77 ◽  
Author(s):  
Hans-Jürgen Hinz ◽  
Peter Pollwein ◽  
Renate Schmidt ◽  
Franz Zimmermann
Keyword(s):  
Guanosine Triphosphate ◽  
Enthalpy Changes ◽  
Hydrolysis Of

Ribonucleotide Reductase in Immature Testes of Salmon

1971 ◽  
Vol 28 (10) ◽  
pp. 1603-1608
Author(s):  
H. L. A. Tarr ◽  
Linda Gardner
Keyword(s):  
Acid Hydrolysis ◽  
Ribonucleotide Reductase ◽  
Specific Radioactivity ◽  
Crude Enzyme ◽  
Guanosine Triphosphate ◽  
Phosphatase Activities ◽  
Guanosine Diphosphate ◽  
Allosteric Effectors ◽  
Specific Activities ◽  
Hydrolysis Of

When cell-free extracts obtained by ultracentrifugation of homogenates of immature salmon testes were incubated with radioactive ribonucleoside di- or triphosphates, the corresponding deoxyribonucleosides were isolated from the reaction mixtures. The specific activities of the crude enzyme extracts were between 15.8 and 54 picomoles of deoxyribonucleoside formed per milligram of protein per hour at 25 C. All attempts to purify the enzyme, which lost activity quite rapidly at 0 C, were unsuccessful. Acid hydrolysis of guanosine deoxyribosides of constant specific radioactivity formed by enzymic reduction of tritiated guanosine triphosphate (GTP) or guanosine diphosphate (GDP) yielded radioactive guanosine of similar specific radioactivity. The crude nature of the preparation, which possessed phosphoribokinase and phosphatase activities, made it impossible to decide whether nucleotide reduction occurred at the mono-, di-, or triphosphate level. Evidence was obtained that allosteric effectors are required for ribonucleotide reduction, as with mammalian and bacterial ribonucleoside diphosphate reductase. The enzyme required dithiothreitol and iron, was strongly stimulated by ethylenediaminetetraacetate (EDTA) and was inhibited by dADP.

Fine Structural Localization of Acyltransferases Involved in Lipid Synthesis in Intestinal Mucosa.

1970 ◽  
Vol 28 ◽  
pp. 54-55
Author(s):  
R. J. Barrnett ◽  
J. A. Higgins
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Lipid Synthesis ◽  
Mucosal Cell ◽  
Structural Localization ◽  
Morphological Studies ◽  
Mucosal Cells ◽  
Initial Appearance ◽  
Sh Group ◽  
Hydrolysis Of ◽  
Intestinal Mucosal Cells

The main products of intestinal hydrolysis of dietary triglycerides are free fatty acids and monoglycerides. These form micelles from which the lipids are absorbed across the mucosal cell brush border. Biochemical studies have indicated that intestinal mucosal cells possess a triglyceride synthesising system, which uses monoglyceride directly as an acylacceptor as well as the system found in other tissues in which alphaglycerophosphate is the acylacceptor. The former pathway is used preferentially for the resynthesis of triglyceride from absorbed lipid, while the latter is used mainly for phospholipid synthesis. Both lipids are incorporated into chylomicrons. Morphological studies have shown that during fat absorption there is an initial appearance of fat droplets within the cisternae of the smooth endoplasmic reticulum and that these subsequently accumulate in the golgi elements from which they are released at the lateral borders of the cell as chylomicrons.We have recently developed several methods for the fine structural localization of acyltransferases dependent on the precipitation, in an electron dense form, of CoA released during the transfer of the acyl group to an acceptor, and have now applied these methods to a study of the fine structural localization of the enzymes involved in chylomicron lipid biosynthesis. These methods are based on the reduction of ferricyanide ions by the free SH group of CoA.

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