Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Erythrocyte enzyme activities in patients with reticulocytosis or transient erythroblastopenia show that loss of age-dependent enzyme activity is not a simple exponential process occurring throughout the life-span of the cell. In vivo studies of reticulocyte maturation in rabbits indicate that there are multiple mechanisms of enzyme decay, and that proteolysis continues after the maturation of (morphologically recognisable) reticulocytes into young erythrocytes. Most reticulocyte hexokinase is degraded by lysosomal proteolysis, apparently triggered by an initial attack by lipoxygenase.
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PMID:The loss of enzyme activity from erythroid cells during maturation. 180 84

In rabbit reticulocytes more than half of the total hexokinase activity is mitochondrial bound and shows a fast decay during reticulocyte maturation. During in vitro incubation of rabbit reticulocytes, Ca2+ increases the decay of hexokinase while salicylhydroxamate (SHAM), an inhibitor of lipoxygenase, reduces the decay. Swelling of mitochondria, by incubation of the cells in hypotonic solutions, greatly enhances hexokinase decay, but both the Ca2+ and SHAM are still appreciable suggesting that Ca2+ and the swelling act by additive mechanisms, both able to influence hexokinase decay. This was confirmed by incubation of rabbit brain mitochondria in hypotonic solutions which does not promote any hexokinase decay, while the presence of Ca2+ does. Analyses of hexokinase isozymic pattern after incubation of reticulocytes in hypotonic solution both with and without Ca2+ and SHAM showed that the decay of hexokinase mainly involves the mitochrondrial bound isozymic forms.
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PMID:Effects of Ca2+ and lipoxygenase inhibitors on hexokinase degradation in rabbit reticulocytes. 249 38

Both cis and trans unsaturated fatty acids and sodium dodecyl sulfate activated NADPH oxidase in plasma membranes of human neutrophils in the presence of neutrophil cytosol. In contrast, 5,8,11,14-icosatetraynoic acid, saturated fatty acids, esters, peroxides and 4 beta-phorbol 12-myristate 13-acetate, a potent activator of protein kinase C, were inactive. 5,8,11,14-icosatetraynoic acid inhibited superoxide formation elicited by fatty acids. Guanosine 5'[gamma-thio]triphosphate (GTP[gamma S]), a potent activator of guanine-nucleotide-binding proteins (N-proteins) enhanced superoxide formation elicited by fatty acids up to fourfold, supporting our previous suggestion that NADPH oxidase is regulated by an N-protein [Seifert, R. et al. (1986) FEBS Lett. 205, 161-165]. Cytosols from various tissues, soybean lipoxygenase and protein kinase C, purified from chicken stomach, did not substitute neutrophil cytosol. The activity of neutrophil cytosol was destroyed by heating at 95 degrees C. Superoxide formation was not affected by the inhibitor of protein kinase C 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7). Removal of cytosolic ATP by preincubation with hexokinase and glucose, dialysis of neutrophil cytosol or chelation of calcium with EGTA did not abolish the stimulatory effect of arachidonic acid and GTP[gamma S]. Thus, the cytosolic cofactor appears to be a neutrophil-specific and heat-labile protein, which is neither a lipoxygenase nor protein kinase C.
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PMID:Fatty-acid-induced activation of NADPH oxidase in plasma membranes of human neutrophils depends on neutrophil cytosol and is potentiated by stable guanine nucleotides. 354 90