scholarly journals Site-directed mutagenesis of K396R of the 65 kDa glutamic acid decarboxylase active site obliterates enzyme activity but not antibody binding

FEBS Letters ◽  
2001 ◽  
Vol 488 (3) ◽  
pp. 185-189 ◽  
Author(s):  
Christiane S. Hampe ◽  
Lisa P. Hammerle ◽  
Alberto Falorni ◽  
John Robertson ◽  
Åke Lernmark
Keyword(s):  
Enzyme Activity ◽  
Glutamic Acid ◽  
Glutamic Acid Decarboxylase ◽  
Active Site ◽  
Antibody Binding ◽  
Site Directed Mutagenesis ◽  
Acid Decarboxylase ◽  
Directed Mutagenesis

scholarly journals Site-directed mutagenesis of active-site-related residues inTorpedoacetylcholinesterase Presence of a glutamic acid in the catalytic triad

FEBS Letters ◽  
1992 ◽  
Vol 309 (3) ◽  
pp. 421-423 ◽  
Author(s):  
Nathalie Duval ◽  
Suzanne Bon ◽  
Israel Silman ◽  
Joel Sussman ◽  
Jean Massoulié
Keyword(s):  
Glutamic Acid ◽  
Active Site ◽  
Catalytic Triad ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis

scholarly journals Ferulic Acid Inhibits Catamenial Epilepsy Through Modulation of Female Hormones

2021 ◽  
Author(s):  
Harleen Kaur Dhillon ◽  
Tanveer Singh ◽  
Rajesh Kumar Goel
Keyword(s):  
Enzyme Activity ◽  
Glutamic Acid ◽  
Ferulic Acid ◽  
Glutamic Acid Decarboxylase ◽  
Intractable Epilepsy ◽  
Acid Decarboxylase ◽  
Seizure Susceptibility ◽  
Catamenial Epilepsy ◽  
Cyclic Changes ◽  
Estradiol Levels

Abstract Approximately 40% of women with epilepsy experience perimenstrual seizure exacerbation, referred to as catamenial epilepsy. These seizures result from cyclic changes in circulating progesterone and estradiol levels and there is no effective treatment for this form of intractable epilepsy. We artificially increased progesterone levels and neurosteroid levels (pseudo-pregnancy) in adult Swiss albino female mice (19-23 g) by injecting them with pregnant mares' serum gonadotropin (5 IU s.c.), followed by human chorionic gonadotropin (5 IU s.c.) after 46 hours. After this, ferulic acid (25, 50, 100 mg/kg i.p.) treatment was observed for 10 days. During treatment, progesterone, estradiol, and corticosterone levels were estimated in blood on days 1, 5, and 10. Neurosteroid withdrawal was induced by finasteride (50 mg/kg, i.p.), a 5 α-reductase inhibitor on treatment day 9. Twenty-four hours after finasteride administration (day 10 of treatment), seizure susceptibility was evaluated with the sub-convulsant pentylenetetrazol (PTZ) dose (40 mg/kg i.p.). Four to six hours after PTZ, animals were assessed for depression like phenotypes using tail-suspension test (TST). Four to six hours following TST, animals were euthanized, and discrete brain parts (cortex and hippocampus) were separated for estimation of norepinephrine, serotonin, and dopamine as well as glutamic acid decarboxylase enzyme activity. PMSG and HCG treatment elevated progesterone and estradiol levels, assessed on days 1, 5, and 10 causing a state of pseudo-pregnancy. Treatment with finasteride increases seizure susceptibility and depression-like characteristics possibly due to decreased progesterone levels and elevated estrogen levels coupled with decreased monoamine and elevated corticosterone levels. Ferulic acid treatment, on the other hand, significantly decreased seizure susceptibility and depression like behaviours, possibly as a result of increased progesterone, restored estradiol, corticosterone, monoamine, and glutamic acid decarboxylase enzyme activity. We concluded that ferulic acid exhibited antiepileptic effects in a mouse model of catamenial epilepsy and comorbid depression due to its restorative effects on circulating hormones and cerebral monoamine and glutamic acid decarboxylase enzyme activity.

γ-Aminobutyric acid activity in the olfactory bulb of the rat during the sexual cycle and response to olfactory stimuli

1992 ◽  
Vol 70 (6) ◽  
pp. 922-925 ◽  
Author(s):  
N. Navarro Becerra ◽  
N. I. Munaro
Keyword(s):  
Enzyme Activity ◽  
Circadian Rhythm ◽  
Olfactory Bulb ◽  
Glutamic Acid ◽  
Glutamic Acid Decarboxylase ◽  
Sexual Cycle ◽  
Acid Decarboxylase ◽  
Decarboxylase Activity ◽  
Male Odor ◽  
Olfactory Stimuli

Glutamic acid decarboxylase activity in the main and accessory olfactory bulbs throughout the sexual cycle of the rat was studied. The effect of male pheromonal secretion on enzyme activity during proestrus and estrus day was also tested. The enzyme activity showed circadian rhythm during the estrous cycle. This rhythm was disrupted during diestrus-2 afternoon in the main bulb and came back during proestrus afternoon. A different pattern of enzyme activity was present in the accessory bulb, since the circadian rhythm was altered during proestrus morning, returning during estrus afternoon. Male odor exposition did not change enzyme profile activity during proestrus day and during estrus morning in the main bulb. In contrast, in the accessory bulb the olfactory stimuli induced opposite changes to that found in rats from the vivarium during proestrus. Comparison of enzyme activity in olfactory stimuli-deprived rats with that of pheromone-stimulated rats during proestrus showed that male odor exposure specifically affects accessory bulb enzyme activity. It is concluded that the changes of the olfactory bulb GABAergic system during proestrus and estrus day, or that evoked by odor stimuli, demonstrate the discriminative response of this system between the accessory olfactory bulb and the main olfactory bulb.Key words: glutamic acid decarboxylase, pheromone, olfactory bulb, GABA, sexual cycle.

scholarly journals Amino acid residues 24-31 but not palmitoylation of cysteines 30 and 45 are required for membrane anchoring of glutamic acid decarboxylase, GAD65

1994 ◽  
Vol 124 (6) ◽  
pp. 927-934 ◽  
Author(s):  
Y Shi ◽  
B Veit ◽  
S Baekkeskov
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Beta Cells ◽  
Glutamic Acid Decarboxylase ◽  
Pancreatic Beta Cells ◽  
Terminal Region ◽  
Site Directed Mutagenesis ◽  
Acid Decarboxylase ◽  
Post Translational Modification ◽  
Membrane Anchoring

The smaller isoform of the GABA synthesizing enzyme glutamic acid decarboxylase, GAD65, is synthesized as a soluble protein that undergoes post-translational modification(s) in the NH2-terminal region to become anchored to the membrane of small synaptic-like microvesicles in pancreatic beta cells, and synaptic vesicles in GABA-ergic neurons. A soluble hydrophilic form, a soluble hydrophobic form, and a hydrophobic firmly membrane-anchored form have been detected in beta cells. A reversible and hydroxylamine sensitive palmitoylation has been shown to distinguish the firmly membrane-anchored form from the soluble yet hydrophobic form, suggesting that palmitoylation of cysteines in the NH2-terminal region is involved in membrane anchoring. In this study we use site-directed mutagenesis to identify the first two cysteines in the NH2-terminal region, Cys 30 and Cys 45, as the sites of palmitoylation of the GAD65 molecule. Mutation of Cys 30 and Cys 45 to Ala results in a loss of palmitoylation but does not significantly alter membrane association of GAD65 in COS-7 cells. Deletion of the first 23 amino acids at the NH2 terminus of the GAD65 30/45A mutant also does not affect the hydrophobicity and membrane anchoring of the GAD65 protein. However, deletion of an additional eight amino acids at the NH2 terminus results in a protein which is hydrophilic and cytosolic. The results suggest that amino acids 24-31 are required for hydrophobic modification and/or targeting of GAD65 to membrane compartments, whereas palmitoylation of Cys 30 and Cys 45 may rather serve to orient or fold the protein at synaptic vesicle membranes.

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