Rahman N

References (3)

Title : Comparison of the Structure and Activity of Glycosylated and Aglycosylated Human Carboxylesterase 1 - Arena de Souza_2015_PLoS.One_10_e0143919
Author(s) : Arena de Souza V , Scott DJ , Nettleship JE , Rahman N , Charlton MH , Walsh MA , Owens RJ
Ref : PLoS ONE , 10 :e0143919 , 2015
Abstract : Human Carboxylesterase 1 (hCES1) is the key liver microsomal enzyme responsible for detoxification and metabolism of a variety of clinical drugs. To analyse the role of the single N-linked glycan on the structure and activity of the enzyme, authentically glycosylated and aglycosylated hCES1, generated by mutating asparagine 79 to glutamine, were produced in human embryonic kidney cells. Purified enzymes were shown to be predominantly trimeric in solution by analytical ultracentrifugation. The purified aglycosylated enzyme was found to be more active than glycosylated hCES1 and analysis of enzyme kinetics revealed that both enzymes exhibit positive cooperativity. Crystal structures of hCES1 a catalytically inactive mutant (S221A) and the aglycosylated enzyme were determined in the absence of any ligand or substrate to high resolutions (1.86 A, 1.48 A and 2.01 A, respectively). Superposition of all three structures showed only minor conformational differences with a root mean square deviations of around 0.5 A over all Calpha positions. Comparison of the active sites of these un-liganded enzymes with the structures of hCES1-ligand complexes showed that side-chains of the catalytic triad were pre-disposed for substrate binding. Overall the results indicate that preventing N-glycosylation of hCES1 does not significantly affect the structure or activity of the enzyme.
ESTHER : Arena de Souza_2015_PLoS.One_10_e0143919
PubMedSearch : Arena de Souza_2015_PLoS.One_10_e0143919
PubMedID: 26657071
Gene_locus related to this paper: human-CES1

Title : Rectal biopsy for Hirschsprung's disease--are we performing too many? - Rahman_2010_Eur.J.Pediatr.Surg_20_95
Author(s) : Rahman N , Chouhan J , Gould S , Joseph V , Grant H , Hitchcock R , Johnson P , Lakhoo K
Ref : European Journal of Pediatric Surgery , 20 :95 , 2010
Abstract : BACKGROUND: Rectal biopsy is considered the gold standard for the diagnosis of Hirschsprung's disease. The aim of this study was to evaluate the outcome of rectal biopsies performed in our institution, and to determine whether we are performing an adequate number of biopsies in patients presenting with features suggestive of this disease. METHODS: A retrospective analysis was conducted of patients who underwent rectal biopsy to exclude Hirschsprung's disease over a seven year period between 2000 and 2006. The histological diagnosis of Hirschsprung's disease was made using haematoxylin and eosin as well as acetylcholinesterase on frozen section. Patients were grouped into three age categories: neonates (group A), infants (group B) and those over 1 year of age (group C). The results of the biopsies were compared between groups. RESULTS: A total of 668 patients underwent rectal biopsy. 18 samples were insufficient. Based on the histological studies of 650 suitable samples, 73 (11%) were positive and 577 (89%) were negative for Hirschsprung's disease. Of the 73 positive biopsies, 34 (47%) were from group A, 20 (27%) from group B and 19 (26%) from group C. The percentage of positive biopsies was much higher in group A with 29% (34 out of 118) compared to group B with 15% (20 out of 135) and group C with 5% (19 out of 395). Three complications of minor rectal bleeding occurred. CONCLUSIONS: With 3 complications and 18 insufficient samples out of 668, rectal biopsy is a safe procedure and remains the gold standard for the diagnosis of Hirschsprung's disease, despite the large number of negative biopsies. Contrary to some reports in the literature which question the need for rectal biopsy in those presenting after the neonatal period, 53% of our positive diagnoses were made in children presenting after this period, with 19 positive biopsies out of 395 (5%) performed in children above the age of 1 year.
ESTHER : Rahman_2010_Eur.J.Pediatr.Surg_20_95
PubMedSearch : Rahman_2010_Eur.J.Pediatr.Surg_20_95
PubMedID: 20397119

Title : Hormone-sensitive lipase is critical mediators of acute exercise-induced regulation of lipolysis in rat adipocytes - Ogasawara_2010_Biochem.Biophys.Res.Commun_400_134
Author(s) : Ogasawara J , Nomura S , Rahman N , Sakurai T , Kizaki T , Izawa T , Ishida H , Haga S , Ohno H
Ref : Biochemical & Biophysical Research Communications , 400 :134 , 2010
Abstract : The purpose of the present study was to investigate the effect of acute exercise on lipolysis via coordination of hormone-sensitive lipase (HSL) and scaffold proteins, i.e., perilipin A and comparative gene identification-58 (CGI-58), in rat primary adipocytes. Glycerol release was significantly elevated immediately (0h) and three hours (3h) after exercise. Both activity and localization to the pellet of HSL were significantly greater in the pellet fraction, which is included in lipid droplet associated-proteins, than in the supernatant fraction. In the pellet fraction, although neither perilipin A nor CGI-58 protein level changed, level of perilipin A/CGI-58 complex was significantly reduced, accompanied by up-regulated association of perilipin A/HSL at 0h and 3h after exercise. On the other hand, there were no changes in these molecules at 24h after exercise, despite a significant decrease in lipolysis that was observed in response to isoproterenol. These findings suggest that acute exercise enhances lipolysis up to at least 3h after exercise in a manner dependent on modification of HSL and its association with and alteration in scaffold protein.
ESTHER : Ogasawara_2010_Biochem.Biophys.Res.Commun_400_134
PubMedSearch : Ogasawara_2010_Biochem.Biophys.Res.Commun_400_134
PubMedID: 20708600