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Article ; Online: Polyphenol-rich Boswellia serrata gum prevents cognitive impairment and insulin resistance of diabetic rats through inhibition of GSK3β activity, oxidative stress and pro-inflammatory cytokines.

Gomaa, Adel A / Makboul, Rania M / Al-Mokhtar, Mohamed A / Nicola, Mariam A

Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie

2018 Volume 109, Page(s) 281–292

Abstract: Type 2 diabetes (T2D) is associated with accelerated cognitive decline. To date, there is no T2D-specific treatment to prevent or ameliorate cognitive dysfunction. Boswellia serrate (BS) gum has been shown to possess multiple pharmacological actions ... ...

Abstract	Type 2 diabetes (T2D) is associated with accelerated cognitive decline. To date, there is no T2D-specific treatment to prevent or ameliorate cognitive dysfunction. Boswellia serrate (BS) gum has been shown to possess multiple pharmacological actions including anti-inflammatory, anticancer and ant- apoptotic actions. The present study was aimed to investigate the effect of BS on cognitive impairment associated with T2D induced in rats by high fat/high fructose (HF/HFr) diet with a single injection of streptozotocin (STZ) and to explore the mechanism of action. The effect of 3 doses of BS extract and the reference drug on the behavioral, biochemical, histopathological and glutamate gene expression abnormalities in T2D rates was evaluated. HF/HFr diet/ STZ induces learning and memory deficits, which were reversed by BS extract. It showed a significant decrease in Aβ deposits and p-tau positive cells. BS extract also reduced significantly the hippocampal elevated levels of caspase-3, cholinesterase (ChE), GSK-3β, TNF-α, IL-1β, IL-6, and MDA. Moreover, BS extract enhanced significantly the suppressed hippocampal level of GSH, SOD and glutamate receptor expression (GluR, NR1, NR2 A, and NR2B). In addition, BS extract alleviated insulin resistance and hyperlipidemia of T2D rats. Our findings suggest that BS extract reversed learning and memory impairment in HF/ HFr diet / STZ induced diabetic rats. This effect may be attributed to the inhibition of insulin resistance, pro-inflammatory cytokines, oxidative stress and hyperlipidemia.
MeSH term(s)	Animals ; Boswellia ; Cognitive Dysfunction/drug therapy ; Cognitive Dysfunction/metabolism ; Cytokines/antagonists & inhibitors ; Cytokines/metabolism ; Diabetes Mellitus, Experimental/drug therapy ; Diabetes Mellitus, Experimental/metabolism ; Dose-Response Relationship, Drug ; Enzyme Inhibitors/isolation & purification ; Enzyme Inhibitors/pharmacology ; Enzyme Inhibitors/therapeutic use ; Glycogen Synthase Kinase 3 beta/antagonists & inhibitors ; Glycogen Synthase Kinase 3 beta/metabolism ; Inflammation Mediators/antagonists & inhibitors ; Inflammation Mediators/metabolism ; Insulin Resistance/physiology ; Male ; Maze Learning/drug effects ; Maze Learning/physiology ; Mice ; Oxidative Stress/drug effects ; Oxidative Stress/physiology ; Plant Extracts ; Plant Gums/isolation & purification ; Plant Gums/pharmacology ; Plant Gums/therapeutic use ; Polyphenols/isolation & purification ; Polyphenols/pharmacology ; Polyphenols/therapeutic use ; Rats ; Rats, Wistar
Chemical Substances	Cytokines ; Enzyme Inhibitors ; Inflammation Mediators ; Plant Extracts ; Plant Gums ; Polyphenols ; Glycogen Synthase Kinase 3 beta (EC 2.7.11.1)
Language	English
Publishing date	2018-11-03
Publishing country	France
Document type	Journal Article
ZDB-ID	392415-4
ISSN	1950-6007 ; 0753-3322 ; 0300-0893
ISSN (online)	1950-6007
ISSN	0753-3322 ; 0300-0893
DOI	10.1016/j.biopha.2018.10.056
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Article ; Online: Osteoid osteoma of the cuboid managed by percutaneous radiofrequency ablation.

Chakraverty, Julian / Al-Mokhtar, Namir / James, Steven L

The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons

2014 Volume 53, Issue 2, Page(s) 212–215

Abstract: We present details of a case of osteoid osteoma of the tarsal cuboid bone. Osteoid osteoma arising in the foot is not very common, and localization in the cuboid is rare. To our knowledge, this is the first case of osteoid osteoma of the cuboid bone ... ...

Abstract	We present details of a case of osteoid osteoma of the tarsal cuboid bone. Osteoid osteoma arising in the foot is not very common, and localization in the cuboid is rare. To our knowledge, this is the first case of osteoid osteoma of the cuboid bone treated successfully by percutaneous radiofrequency ablation.
MeSH term(s)	Bone Neoplasms/diagnosis ; Bone Neoplasms/surgery ; Catheter Ablation ; Humans ; Male ; Osteoma, Osteoid/diagnosis ; Osteoma, Osteoid/surgery ; Tarsal Bones ; Young Adult
Language	English
Publishing date	2014-03
Publishing country	United States
Document type	Journal Article
ZDB-ID	1146972-9
ISSN	1542-2224 ; 1067-2516
ISSN (online)	1542-2224
ISSN	1067-2516
DOI	10.1053/j.jfas.2013.12.003
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Article: Initial clinical experience of the use of digital tomosynthesis in the assessment of suspected fracture neck of femur in the elderly.

Al-Mokhtar, Namir / Shah, Jaydeep / Marson, Ben / Evans, Simon / Nye, Katelyn

European journal of orthopaedic surgery & traumatology : orthopedie traumatologie

2015 Volume 25, Issue 5, Page(s) 941–947

Abstract: Objective: This study was undertaken to evaluate the use of digital tomosynthesis (tomogram) for diagnosis of suspected fracture neck of femur (NOF). We hypothesised that the use of cross-sectional imaging (MRI/CT) could be reduced by using tomogram to ... ...

Abstract	Objective: This study was undertaken to evaluate the use of digital tomosynthesis (tomogram) for diagnosis of suspected fracture neck of femur (NOF). We hypothesised that the use of cross-sectional imaging (MRI/CT) could be reduced by using tomogram to separate the patients with suspected NOF fractures that require MRI/CT scan from those who do not. Materials and method: Forty-one patients with a clinically suspected NOF fracture, following trauma, with negative AP and lateral hip X-rays, underwent a hip tomogram examination. Patients with a negative tomogram and clinically moderate to high probability of a hip fracture underwent MRI/CT within 48 h. Result: Tomogram identified fracture NOF in six patients, who underwent appropriate surgical treatment without needing further imaging. Fifteen patients, with negative tomogram examinations for fracture NOF and a low clinical probability of a fracture did not undergo additional MRI/CT scanning. At 6 months of follow-up, none of the patients returned to the hospital with complications. Twenty patients with moderate to high clinical probability of fracture NOF with negative or inconclusive tomogram underwent additional MRI/CT scanning (19 MRI, 1 CT). Two patients showed fracture NOF, and one patient with greater trochanter fracture on tomogram showed fracture NOF on MRI scan. Seventeen patients showed soft tissue injury, bone oedema or pubic rami/acetabular fractures on MRI scan. Conclusion: Tomogram is a reliable imaging modality that can be used to select the patients who will need additional MRI/CT scan following negative or equivocal plain X-ray in patients with suspected hip fractures following fall. Level of evidence: III.
MeSH term(s)	Aged ; Aged, 80 and over ; Female ; Femoral Neck Fractures/diagnosis ; Femoral Neck Fractures/diagnostic imaging ; Femur Neck/diagnostic imaging ; Humans ; Magnetic Resonance Imaging/methods ; Male ; Sensitivity and Specificity ; Tomography, X-Ray Computed/methods
Language	English
Publishing date	2015-07
Publishing country	France
Document type	Journal Article
ZDB-ID	1231084-0
ISSN	1432-1068 ; 1633-8065 ; 0948-4817 ; 0940-3264
ISSN (online)	1432-1068
ISSN	1633-8065 ; 0948-4817 ; 0940-3264
DOI	10.1007/s00590-015-1632-3
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Article: Effects of glucocorticoids on vitamin D3-metabolizing 24-hydroxylase (CYP24A1) in Saos-2 cells and primary human osteoblasts

Zayny, Ahmad / Almokhtar, Mokhtar / Wikvall, Kjell / Ljunggren, Östen / Ubhayasekera, Kumari / Bergquist, Jonas / Kibar, Pinar / Norlin, Maria

Molecular and cellular endocrinology. 2019 Oct. 01, v. 496

2019

Abstract: Vitamin D is essential for bone function and deficiency in active vitamin D hormone can lead to bone disorders. Long-term treatment with glucocorticoids results in osteoporosis and increased risk of fractures. Much remains unclear regarding the effects ... ...

Abstract	Vitamin D is essential for bone function and deficiency in active vitamin D hormone can lead to bone disorders. Long-term treatment with glucocorticoids results in osteoporosis and increased risk of fractures. Much remains unclear regarding the effects of these compounds in bone cells. In the current study, human osteosarcoma Saos-2 cells and primary human osteoblasts were found to express mRNA for the vitamin D receptor as well as activating and deactivating enzymes in vitamin D3 metabolism. These bone cells exhibited CYP24A1-mediated 24-hydroxylation which is essential for deactivation of the active vitamin form. However, bioactivating vitamin D3 hydroxylase activities could not be detected in either of these cells. Several glucocorticoids, including prednisolone, down regulated CYP24A1 mRNA and CYP24A1-mediated 24-hydroxylase activity in both Saos-2 and primary human osteoblasts. Also, prednisolone significantly suppressed a human CYP24A1 promoter-luciferase reporter gene in Saos-2 cells co-transfected with the glucocorticoid receptor. Thus, the results of the present study show suppression by glucocorticoids on CYP24A1 mRNA, CYP24A1-mediated metabolism and CYP24A1 promoter activity in human osteoblast-like cells. As part of this study we examined if glucocorticoids are formed locally in Saos-2 cells. The experiments indicate formation of 11-deoxycortisol, a steroid with glucocorticoid activity, which can bind the glucocorticoid receptor. Our data showing suppression by glucocorticoids on CYP24A1 expression in human osteoblasts suggest a previously unknown mechanism for effects of glucocorticoids in human bone, where these compounds may interfere with regulation of active vitamin D levels.
Keywords	calcitriol receptors ; cholecalciferol ; enzyme activity ; enzymes ; gene expression regulation ; glucocorticoid receptors ; glucocorticoids ; humans ; messenger RNA ; metabolism ; osteoblasts ; osteoporosis ; osteosarcoma ; prednisolone ; reporter genes ; risk
Language	English
Dates of publication	2019-1001
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	187438-x
ISSN	1872-8057 ; 0303-7207
ISSN (online)	1872-8057
ISSN	0303-7207
DOI	10.1016/j.mce.2019.110525
Database	NAL-Catalogue (AGRICOLA)

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Zs.A 1127: Show issues

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Article ; Online: Effects of glucocorticoids on vitamin D

Zayny, Ahmad / Almokhtar, Mokhtar / Wikvall, Kjell / Ljunggren, Östen / Ubhayasekera, Kumari / Bergquist, Jonas / Kibar, Pinar / Norlin, Maria

Molecular and cellular endocrinology

2019 Volume 496, Page(s) 110525

Abstract	Vitamin D is essential for bone function and deficiency in active vitamin D hormone can lead to bone disorders. Long-term treatment with glucocorticoids results in osteoporosis and increased risk of fractures. Much remains unclear regarding the effects of these compounds in bone cells. In the current study, human osteosarcoma Saos-2 cells and primary human osteoblasts were found to express mRNA for the vitamin D receptor as well as activating and deactivating enzymes in vitamin D
MeSH term(s)	Cell Line, Tumor ; Cholecalciferol/metabolism ; Gene Expression Regulation, Enzymologic/drug effects ; Glucocorticoids/pharmacology ; Humans ; Osteoblasts/cytology ; Osteoblasts/enzymology ; Promoter Regions, Genetic ; Vitamin D3 24-Hydroxylase/biosynthesis ; Vitamin D3 24-Hydroxylase/genetics
Chemical Substances	Glucocorticoids ; Cholecalciferol (1C6V77QF41) ; CYP24A1 protein, human (EC 1.14.15.16) ; Vitamin D3 24-Hydroxylase (EC 1.14.15.16)
Language	English
Publishing date	2019-07-25
Publishing country	Ireland
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	187438-x
ISSN	1872-8057 ; 0303-7207
ISSN (online)	1872-8057
ISSN	0303-7207
DOI	10.1016/j.mce.2019.110525
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Article ; Online: Motor neuron-like NSC-34 cells as a new model for the study of vitamin D metabolism in the brain.

Almokhtar, Mokhtar / Wikvall, Kjell / Ubhayasekera, S J Kumari A / Bergquist, Jonas / Norlin, Maria

The Journal of steroid biochemistry and molecular biology

2016 Volume 158, Page(s) 178–188

Abstract: Vitamin D3 is a pro-hormone, which is sequentially activated by 25- and 1α-hydroxylation to form 25-hydroxyvitamin D3 [25(OH)D3] and 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], respectively. Subsequent inactivation is performed by 24-hydroxylation. These ... ...

Abstract	Vitamin D3 is a pro-hormone, which is sequentially activated by 25- and 1α-hydroxylation to form 25-hydroxyvitamin D3 [25(OH)D3] and 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], respectively. Subsequent inactivation is performed by 24-hydroxylation. These reactions are carried out by a series of CYP450 enzymes. The 25-hydroxylation involves mainly CYP2R1 and CYP27A1, whereas 1α-hydroxylation and 24-hydroxylation are catalyzed by CYP27B1 and CYP24A1, respectively, and are tightly regulated to maintain adequate levels of the active vitamin D hormone, 1α,25(OH)2D3. Altered circulating vitamin D levels, in particular 25(OH)D3, have been linked to several disorders of the nervous system, e.g., schizophrenia and Parkinson disease. However, little is known about the mechanisms of vitamin D actions in the neurons. In this study, we examined vitamin D metabolism and its regulation in a murine motor neuron-like hybrid cell line, NSC-34. We found that these cells express mRNAs for the four major CYP450 enzymes involved in vitamin D activation and inactivation, and vitamin D receptor (VDR) that mediates vitamin D actions. We also found high levels of CYP24A1-dependent 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] production, that was inhibited by the well-known CYP enzyme inhibitor ketoconazole and by several inhibitors that are more specific for CYP24A1. Furthermore, CYP24A1 mRNA levels in NSC-34 cells were up-regulated by 1α,25(OH)2D3 and its synthetic analogs, EB1089 and tacalcitol. Our results suggest that NSC-34 cells could be a novel model for the studies of neuronal vitamin D metabolism and its mechanism of actions.
MeSH term(s)	Animals ; Brain/metabolism ; Cell Line, Tumor ; Cytochrome P-450 Enzyme Inhibitors/pharmacology ; Cytochrome P-450 Enzyme System/genetics ; Mice ; Motor Neurons/metabolism ; RNA, Messenger/metabolism ; Receptors, Calcitriol/genetics ; Vitamin D/metabolism
Chemical Substances	Cytochrome P-450 Enzyme Inhibitors ; RNA, Messenger ; Receptors, Calcitriol ; Vitamin D (1406-16-2) ; Cytochrome P-450 Enzyme System (9035-51-2)
Language	English
Publishing date	2016-04
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1049188-0
ISSN	1879-1220 ; 0960-0760
ISSN (online)	1879-1220
ISSN	0960-0760
DOI	10.1016/j.jsbmb.2015.12.010
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Zs.A 708: Show issues

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Article ; Online: De-speckling 2D-Discrete Wavelet Transform with Hard Threshold Stage

Dhafer Hasan / Maha Abdul-Jabar / Zahraa Abed Al-Mokhtar

Al-Rafidain Journal of Computer Sciences and Mathematics, Vol 9, Iss 1, Pp 101-

2012 Volume 112

Abstract: In this work, a new method is implemented for removing noise from gray scale image that depends on two-dimensional discrete wavelet transform and Threshold stage (hard threshold). This paper represents the algorithm to remove the speckle noise by using ... ...

Abstract	In this work, a new method is implemented for removing noise from gray scale image that depends on two-dimensional discrete wavelet transform and Threshold stage (hard threshold). This paper represents the algorithm to remove the speckle noise by using logarithm operation. This operation changes the multiplicative noise to additive noise. So that, the removing operation becomes easier. The Matlab program is used to build the Algorithm and measure the PSNR and other measurement criteria as (NMV, NV, NSD, ENL and PSNR) to study the effect of removing noise from corrupted image. The PSNR reaches to 24dB which is very satisfactory result in the reconstructed image, while the maximum value of ENL is 2.23 * 10 6 , and the minimum value of NMV, NV, NSD which is equal to 6.79, 2.6710 -5 , 46 10 -4 respectively gives a smoother and cleaner image. The universal Threshold is applied in high frequency coefficient (i.e. the LH, HL, and HH-sub band of image) to remove the speckle noise and the low frequency coefficient (LL-sub band of image) is still without any change.
Keywords	speckle noise ; discrete wavelet transform ; universal threshold ; logarithmic function ; Mathematics ; QA1-939 ; Electronic computers. Computer science ; QA75.5-76.95
Subject code	333
Language	Arabic
Publishing date	2012-07-01T00:00:00Z
Publisher	Mosul University
Document type	Article ; Online
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Article ; Online: Expression and regulation of CYP17A1 and 3β-hydroxysteroid dehydrogenase in cells of the nervous system: Potential effects of vitamin D on brain steroidogenesis.

Emanuelsson, Ida / Almokhtar, Mokhtar / Wikvall, Kjell / Grönbladh, Alfhild / Nylander, Erik / Svensson, Anne-Lie / Fex Svenningsen, Åsa / Norlin, Maria

Neurochemistry international

2017 Volume 113, Page(s) 46–55

Abstract: Steroids are reported to have diverse functions in the nervous system. Enzymatic production of steroid hormones has been reported in different cell types, including astrocytes and neurons. However, the information on some of the steroidogenic enzymes ... ...

Abstract	Steroids are reported to have diverse functions in the nervous system. Enzymatic production of steroid hormones has been reported in different cell types, including astrocytes and neurons. However, the information on some of the steroidogenic enzymes involved is insufficient in many respects. Contradictory results have been reported concerning the relative importance of different cell types in the nervous system for expression of CYP17A1 and 3β-hydroxysteroid dehydrogenase (3β-HSD). 3β-HSD is important in all basic steroidogenic pathways and CYP17A1 is required to form sex hormones. In the current investigation we studied the expression of these enzymes in cultured primary rat astrocytes, in neuron-enriched cells from rat cerebral cortex and in human neuroblastoma SH-SY5Y cells, a cell line often used as an in vitro model of neuronal function and differentiation. As part of this study we also examined potential effects on CYP17A1 and 3β-HSD by vitamin D, a compound previously shown to have regulatory effects in steroid hormone-producing cells outside the brain. The results of our study indicate that astrocytes are a major site for expression of 3β-HSD whereas expression of CYP17A1 is found in both astrocytes and neurons. The current data suggest that neurons, contrary to some previous reports, are not involved in 3β-HSD reactions. Previous studies have shown that vitamin D can influence gene expression and hormone production by steroidogenic enzymes in some cells. We found that vitamin D suppressed CYP17A1-mediated activity by 20% in SH-SY5Ycells and astrocytes. Suppression of CYP17A1 mRNA levels was considerably stronger, about 50% in SH-SY5Y cells and 75% in astrocytes. In astrocytes 3β-HSD was also suppressed by vitamin D, about 20% at the enzyme activity level and 60% at the mRNA level. These data suggest that vitamin D-mediated regulation of CYP17A1 and 3β-HSD, particularly on the transcriptional level, may play a role in the nervous system.
MeSH term(s)	17-Hydroxysteroid Dehydrogenases/antagonists & inhibitors ; 17-Hydroxysteroid Dehydrogenases/biosynthesis ; 17-Hydroxysteroid Dehydrogenases/genetics ; Animals ; Brain/drug effects ; Brain/enzymology ; Cell Line, Tumor ; Cells, Cultured ; Gene Expression Regulation, Enzymologic/drug effects ; Humans ; Rats ; Rats, Sprague-Dawley ; Steroid 17-alpha-Hydroxylase/antagonists & inhibitors ; Steroid 17-alpha-Hydroxylase/biosynthesis ; Steroid 17-alpha-Hydroxylase/genetics ; Steroids/antagonists & inhibitors ; Steroids/biosynthesis ; Vitamin D/pharmacology
Chemical Substances	Steroids ; Vitamin D (1406-16-2) ; 17-Hydroxysteroid Dehydrogenases (EC 1.1.-) ; 3 (or 17)-beta-hydroxysteroid dehydrogenase (EC 1.1.1.51) ; CYP17A1 protein, human (EC 1.14.14.19) ; Steroid 17-alpha-Hydroxylase (EC 1.14.14.19)
Language	English
Publishing date	2017-11-21
Publishing country	England
Document type	Journal Article
ZDB-ID	283190-9
ISSN	1872-9754 ; 0197-0186
ISSN (online)	1872-9754
ISSN	0197-0186
DOI	10.1016/j.neuint.2017.11.007
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Article ; Online: Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase?

Hurtado, Marcela / Lamsabhi, Al-Mokhtar / Mó, Otilia / Yáñez, Manuel / Guillemin, Jean-Claude

Dalton transactions (Cambridge, England : 2003)

2010 Volume 39, Issue 19, Page(s) 4593–4601

Abstract: The structure and bonding of cyclopentadienylberyllium (CpBeH), magnesium (CpMgH), and calcium (CpCaH) hydrides as well as those of their deprotonated species have been investigated by means of B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) and B3LYP/6-311+G( ... ...

Abstract	The structure and bonding of cyclopentadienylberyllium (CpBeH), magnesium (CpMgH), and calcium (CpCaH) hydrides as well as those of their deprotonated species have been investigated by means of B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) and B3LYP/6-311+G(3df,2p)//QCISD/6-311+G(d,p) density functional theory (DFT) calculations. The three compounds exhibit C(5v) equilibrium conformations in their ground states. For CpBeH the agreement between the calculated geometry and that determined by MW spectroscopy is excellent. CpMgH and CpCaH can be viewed almost as the result of the interaction between a C₅H₅⁻ anion and a XH(+) (X = Mg, Ca) cation. Conversely, for CpBeH the interaction between the C₅H₅ and the BeH subunits is significantly covalent. These compounds exhibit a significant aromaticity, usually named three-dimension aromaticity, in contrast with the unsubstituted cyclopentadiene compound. The CpBeH derivative behaves as a C acid in the gas phase and is less acidic than cyclopentadiene. More importantly, CpMgH and CpCaH, in spite of the X(+δ)H(-δ) polarity exhibited by the X-H bond in the neutral systems, are predicted to be metal acids in the gas phase. Also surprisingly, both the Mg and the Ca derivatives are stronger acids than the Be analogue, and only slightly weaker acids than cyclopentadiene. This somewhat unexpected result is the consequence of two concomitant facts: the lower dissociation energy of the X-H (X = Mg, Ca) bonds with respect to the C-H bonds, and the significantly high electron affinity of the C₅H₅X* (X = Mg, Ca) radicals.
Language	English
Publishing date	2010-05-21
Publishing country	England
Document type	Journal Article
ZDB-ID	1472887-4
ISSN	1477-9234 ; 1364-5447 ; 0300-9246 ; 1477-9226
ISSN (online)	1477-9234 ; 1364-5447
ISSN	0300-9246 ; 1477-9226
DOI	10.1039/b926653d
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Article ; Online: Structure and kinetic characterization of human sperm-specific glyceraldehyde-3-phosphate dehydrogenase, GAPDS.

Chaikuad, Apirat / Shafqat, Naeem / Al-Mokhtar, Ruby / Cameron, Gus / Clarke, Anthony R / Brady, R Leo / Oppermann, Udo / Frayne, Jan / Yue, Wyatt W

The Biochemical journal

2011 Volume 435, Issue 2, Page(s) 401–409

Abstract: hGAPDS (human sperm-specific glyceraldehyde-3-phosphate dehydrogenase) is a glycolytic enzyme essential for the survival of spermatozoa, and constitutes a potential target for non-hormonal contraception. However, enzyme characterization of GAPDS has been ...

Abstract	hGAPDS (human sperm-specific glyceraldehyde-3-phosphate dehydrogenase) is a glycolytic enzyme essential for the survival of spermatozoa, and constitutes a potential target for non-hormonal contraception. However, enzyme characterization of GAPDS has been hampered by the difficulty in producing soluble recombinant protein. In the present study, we have overexpressed in Escherichia coli a highly soluble form of hGAPDS truncated at the N-terminus (hGAPDSΔN), and crystallized the homotetrameric enzyme in two ligand complexes. The hGAPDSΔN-NAD+-phosphate structure maps the two anion-recognition sites within the catalytic pocket that correspond to the conserved Ps site and the newly recognized Pi site identified in other organisms. The hGAPDSΔN-NAD+-glycerol structure shows serendipitous binding of glycerol at the Ps and new Pi sites, demonstrating the propensity of these anion-recognition sites to bind non-physiologically relevant ligands. A comparison of kinetic profiles between hGAPDSΔN and its somatic equivalent reveals a 3-fold increase in catalytic efficiency for hGAPDSΔN. This may be attributable to subtle amino acid substitutions peripheral to the active centre that influence the charge properties and protonation states of catalytic residues. Our data therefore elucidate structural and kinetic features of hGAPDS that might provide insightful information towards inhibitor development.
MeSH term(s)	Animals ; Binding Sites ; Catalysis ; Glyceraldehyde-3-Phosphate Dehydrogenases/chemistry ; Glyceraldehyde-3-Phosphate Dehydrogenases/genetics ; Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism ; Humans ; Isoenzymes/chemistry ; Isoenzymes/metabolism ; Kinetics ; Male ; Models, Biological ; Models, Molecular ; Organ Specificity/genetics ; Phosphates/metabolism ; Protein Binding ; Protein Structure, Secondary ; Rats ; Spermatogenesis/genetics ; Spermatozoa/enzymology ; Spermatozoa/metabolism
Chemical Substances	Isoenzymes ; Phosphates ; Glyceraldehyde-3-Phosphate Dehydrogenases (EC 1.2.1.-)
Language	English
Publishing date	2011-04-15
Publishing country	England
Document type	Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2969-5
ISSN	1470-8728 ; 0006-2936 ; 0306-3275 ; 0264-6021
ISSN (online)	1470-8728
ISSN	0006-2936 ; 0306-3275 ; 0264-6021
DOI	10.1042/BJ20101442
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