Glucose-6-phosphate dehydrogenase in cold hardy insects: Kinetic properties, freezing stabilization, and control of hexose monophosphate shunt activity

1991 ◽  
Vol 21 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Kenneth B. Storey ◽  
Derrick Keefe ◽  
Lauralynn Kourtz ◽  
Janet M. Storey
Keyword(s):  
Kinetic Properties ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Shunt ◽  
Cold Hardy ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
And Control

scholarly journals Glucose-6-phosphate-dehydrogenase-deficient erythrocytes have an impaired shape recovery mechanism

Blood ◽  
1984 ◽  
Vol 63 (5) ◽  
pp. 1198-1202
Author(s):  
E Alhanaty ◽  
M Snyder ◽  
MP Sheetz
Keyword(s):  
Cell Shape ◽  
Shape Recovery ◽  
Cell Function ◽  
Hexose Monophosphate ◽  
Recovery Rates ◽  
Chloromethyl Ketone ◽  
Hexose Monophosphate Shunt ◽  
Recovery Mechanism ◽  
Normal Shape ◽  
Glucose 6 Phosphate Dehydrogenase

In the human erythrocyte, the maintenance of the biconcave disc shape is important for cell viability as well as cell function. Previous studies have indicated the involvement of the hexose monophosphate shunt in the recovery of discoid shape after perturbation of echinocytic agents. In glucose-6-phosphate-dehydrogenase-deficient (Gd- ) erythrocytes, the shunt activity is significantly decreased; thus, it might be expected that the shape recovery rate of Gd- erythrocytes would be decreased. We show here that shape recovery rates in the presence of the shunt stimulator methylene blue are as much as fivefold lower in Gd- erythrocytes. We also show that the protease inhibitor, N- alpha-tosyl-1-phenylalanine-chloromethyl ketone, has no effect on shape recovery in Gd-, whereas it increases normal cell shape recovery rates by 10–30-fold at 50 microM and causes cupping at 200 microM (see companion article by Alhanaty et al.). These changes are not due to reticulocytosis, as other hemolytic disorders do not show such changes. Further, both chronic hemolyzing Gd and A Gd variants show similar abnormal shape recovery behavior, whereas the extent of hemolysis is quite different between variants. Thus, the activity of the hexose monophosphate shunt appears to have a dramatic effect on the rate of reversal of echinocytosis. The lack of shunt activity of Gd cells would necessarily impair their ability to recover normal shape after perturbation.

Hexose Monophosphate Shunt Enzymes in Lung Tumors from Normal and Glucose-6-Phosphate-Dehydrogenase-Deficient Subjects

Oncology ◽  
1988 ◽  
Vol 45 (4) ◽  
pp. 287-291 ◽  
Author(s):  
S. Dessì ◽  
B. Batetta ◽  
R. Cherchi ◽  
R. Onnis ◽  
M. Pisano ◽  
...  
Keyword(s):  
Lung Tumors ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Shunt ◽  
Glucose 6 Phosphate Dehydrogenase

Genetic and biochemical studies of the hexose monophosphate shunt in Neurospora crassa. II. Characterization of biochemical defects of the morphological mutants colonial 2 and colonial 3

1971 ◽  
Vol 17 (6) ◽  
pp. 789-794 ◽  
Author(s):  
John F. Lechner ◽  
Kathyrn E. Fuscaldo ◽  
George Bazinet
Keyword(s):  
Neurospora Crassa ◽  
State Level ◽  
Hexose Monophosphate ◽  
Wild Type Enzyme ◽  
Hexose Monophosphate Shunt ◽  
Acid Dehydrogenase ◽  
Morphological Mutants ◽  
Altered Form ◽  
Glucose 6 Phosphate Dehydrogenase

The two dehydrogenases of the hexose monophosphate shunt, glucose-6-phosphate dehydrogenase and 6-phosphogluconic acid dehydrogenase, were examined in two morphology mutants of Neurospora crassa. Glucose-6-phosphate dehydrogenase extracted from the mutant colonial-2 was found in an altered form as compared to the wild-type enzyme. The second enzyme of the pathway was observed to be abnormal in the mutant colonial-3. In addition, 6-phosphogluconic acid dehydrogenase was found to exhibit non-classical kinetics. The data indicate that the altered morphology exhibited by both colonial-2 and colonial-3 is due to the suboptimal capacity of the hexose monophosphate shunt to function normally. This physiological impairment of the pathway is reflected in a lowered cellular steady-state level of NADP.

scholarly journals Glucose-6-phosphate-dehydrogenase-deficient erythrocytes have an impaired shape recovery mechanism

Blood ◽  
1984 ◽  
Vol 63 (5) ◽  
pp. 1198-1202 ◽  
Author(s):  
E Alhanaty ◽  
M Snyder ◽  
MP Sheetz
Keyword(s):  
Cell Shape ◽  
Shape Recovery ◽  
Cell Function ◽  
Hexose Monophosphate ◽  
Recovery Rates ◽  
Chloromethyl Ketone ◽  
Hexose Monophosphate Shunt ◽  
Recovery Mechanism ◽  
Normal Shape ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract In the human erythrocyte, the maintenance of the biconcave disc shape is important for cell viability as well as cell function. Previous studies have indicated the involvement of the hexose monophosphate shunt in the recovery of discoid shape after perturbation of echinocytic agents. In glucose-6-phosphate-dehydrogenase-deficient (Gd- ) erythrocytes, the shunt activity is significantly decreased; thus, it might be expected that the shape recovery rate of Gd- erythrocytes would be decreased. We show here that shape recovery rates in the presence of the shunt stimulator methylene blue are as much as fivefold lower in Gd- erythrocytes. We also show that the protease inhibitor, N- alpha-tosyl-1-phenylalanine-chloromethyl ketone, has no effect on shape recovery in Gd-, whereas it increases normal cell shape recovery rates by 10–30-fold at 50 microM and causes cupping at 200 microM (see companion article by Alhanaty et al.). These changes are not due to reticulocytosis, as other hemolytic disorders do not show such changes. Further, both chronic hemolyzing Gd and A Gd variants show similar abnormal shape recovery behavior, whereas the extent of hemolysis is quite different between variants. Thus, the activity of the hexose monophosphate shunt appears to have a dramatic effect on the rate of reversal of echinocytosis. The lack of shunt activity of Gd cells would necessarily impair their ability to recover normal shape after perturbation.

Cytoplasmic pH regulation in phorbol ester-activated human neutrophils

1986 ◽  
Vol 251 (1) ◽  
pp. C55-C65 ◽  
Author(s):  
S. Grinstein ◽  
W. Furuya
Keyword(s):  
Metabolic Pathways ◽  
Phorbol Esters ◽  
Ph Regulation ◽  
Human Neutrophils ◽  
Hexose Monophosphate ◽  
Cytoplasmic Ph ◽  
Extracellular Acidification ◽  
Hexose Monophosphate Shunt ◽  
Activated Neutrophils ◽  
Cytoplasmic Acidification

Activation of neutrophils by 12-O-tetradecanoylphorbol-13-acetate (TPA) is accompanied by an initial cytoplasmic acidification, followed by an alkalinizing phase due to Na+-H+ countertransport. The source of the acidification, which is fully expressed by activation with TPA in Na+-free or amiloride-containing media, was investigated. The acidification phase was detected also in degranulated and enucleated cytoplasts, ruling out a major contribution by the nucleus or secretory vesicles. Cytoplasmic acidification was found to be associated with an extracellular acidification, suggesting metabolic generation of H+. Two principal metabolic pathways are stimulated in activated neutrophils: the reduction of O2 by NADPH-oxidase and the hexose monophosphate shunt. A good correlation was found between the activity of these pathways and the changes in cytoplasmic pH. Inhibition of superoxide synthesis prevented the TPA-induced cytoplasmic acidification. Moreover, activation of the hexose monophosphate shunt with permeable NADPH-oxidizing agents (in the absence of TPA) also produced a cytoplasmic acidification. Cytoplasmic acidification was also elicited by exogenous diacylglycerol and by other beta-phorbol diesters, which are activators of the kinase, but not by unesterified phorbol or by alpha-phorbol diesters, which are biologically inactive. The results suggest that the cytoplasmic acidification induced by phorbol esters in neutrophils reflects accumulation of H+ liberated during the metabolic burst that follows activation.

scholarly journals Effect of dithiocyano-methane on hexose monophosphate pathway in the respiratory metabolism of Escherichia coli

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanfeng Chen ◽  
Wenjie Ke ◽  
Huabin Qin ◽  
Siwei Chen ◽  
Limei Qin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Control Group ◽  
Respiratory Metabolism ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Response To Stress ◽  
Glucose Decomposition ◽  
Decomposition Pathway ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract This paper studied the inhibitory effects of dithiocyano-methane (DM) on the glucose decomposition pathway in the respiratory metabolism of Escherichia coli. We investigated the effects of DM on the activities of key enzymes (ATPase and glucose-6-phosphate dehydrogenase, G6PDH), the levels of key product (nicotinamide adenosine denucleotide hydro-phosphoric acid, NADPH), and gene expression in the hexose monophosphate pathway (HMP). The results showed that the minimum inhibitory concentration (MIC) and the minimum bactericide concentration (MBC) of DM against the tested strains were 5.86 mg/L and 11.72 mg/L, respectively. Bacteria exposed to DM at MIC demonstrated an increase in bacterial ATPase and G6PDH activities, NADPH levels, and gene expression in the HMP pathway compared to bacteria in the control group, which could be interpreted as a behavioral response to stress introduced by DM. However, DM at a lethal concentration of 10 × MIC affected glucose decomposition by inhibiting mainly the HMP pathway in E. coli.

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