Sangita Singh
Iowa State University
Detection limitBiogenesisAlkaline phosphataseCystathionine beta synthaseEnzymeChemistryCofactorHemeproteinHemeTranssulfuration pathwayBacteriophagePyridoxal phosphateHomocysteineCysteineCelluloseActive siteBiochemistryStereochemistryLigand
23Publications
8H-index
1,230Citations
Publications 9
Newest
#1Sangita Singh (UM: University of Michigan)H-Index: 8
#2Ruma Banerjee (UM: University of Michigan)H-Index: 86
The role of endogenously produced H2S in mediating varied physiological effects in mammals has spurred enormous recent interest in understanding its biology and in exploiting its pharmacological potential. In these early days in the field of H2S signaling, large gaps exist in our understanding of its biological targets, its mechanisms of action and the regulation of its biogenesis and its clearance. Two branches within the sulfur metabolic pathway contribute to H2S production: (i) the reverse tr...
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#1Sangita Singh (UM: University of Michigan)H-Index: 8
#2David P. BallouH-Index: 68
Last. Ruma BanerjeeH-Index: 86
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Hydrogen sulfide (H2S)1, like nitric oxide and carbon monoxide, is a gaseous signaling molecule (1-3) that elicits a variety of physiological effects. In the cardiovascular system, H2S apparently functions as a vasorelaxant (4) and as a cardioprotective agent (5). A dose-dependent decrease in murine blood pressure by sodium hydrosulfide has been reported (4). Other reported effects of H2S include protection against ischemia reperfusion injury and anti-inflammatory effects in tissues (5, 6). In l...
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#1Venugopal Karunakaran (NU: Northeastern University)H-Index: 14
#2Abdelkrim Benabbas (NU: Northeastern University)H-Index: 13
Last. Paul M. Champion (NU: Northeastern University)H-Index: 2
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Vibrational coherence spectroscopy is used to study the low frequency dynamics of the truncated dimer of human cystathionine β-synthase (CBS). CBS is a pyridoxal-5′-phosphate-dependent heme enzyme with cysteine and histidine axial ligands that catalyzes the condensation of serine and homocysteine to form cystathionine. A strong correlation between the “detuned” coherence spectrum (which probes higher frequencies) and the Raman spectrum is demonstrated, and a rich pattern of modes below 200 cm−1 ...
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Cystathionine β-synthase (CBS) plays a central role in homocysteine metabolism, and malfunction of the enzyme leads to homocystinuria, a devastating metabolic disease. CBS contains a pyridoxal 5′-phosphate (PLP) cofactor which catalyzes the synthesis of cystathionine from homocysteine and serine. Mammalian forms of the enzyme also contain a heme group, which is not involved in catalysis. It may, however, play a regulatory role, since the enzyme is inhibited when CO or NO are bound to the heme. W...
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#1Sangita Singh (UM: University of Michigan)H-Index: 8
#2Dominique Padovani (UM: University of Michigan)H-Index: 17
Last. Ruma BanerjeeH-Index: 86
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Abstract In mammals, the two enzymes in the trans-sulfuration pathway, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), are believed to be chiefly responsible for hydrogen sulfide (H2S) biogenesis. In this study, we report a detailed kinetic analysis of the human and yeast CBS-catalyzed reactions that result in H2S generation. CBS from both organisms shows a marked preference for H2S generation by β-replacement of cysteine by homocysteine. The alternative H2S-generating reactions,...
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#1Sangita Singh (UM: University of Michigan)H-Index: 8
#2Peter Madzelan (NU: University of Nebraska–Lincoln)H-Index: 6
Last. Ruma Banerjee (UM: University of Michigan)H-Index: 86
view all 8 authors...
Abstract In humans, cystathionine β-synthase (CBS) is a hemeprotein, which catalyzes a pyridoxal phosphate (PLP)-dependent condensation reaction. Changes in the heme environment are communicated to the active site, which is ∼20 A away. In this study, we have examined the role of H67 and R266, which are in the second coordination sphere of the heme ligands, H65 and C52, respectively, in modulating the heme’s electronic properties and in transmitting information between the heme and active sites. ...
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#1Taurai Chiku (UM: University of Michigan)H-Index: 4
#2Dominique Padovani (UM: University of Michigan)H-Index: 17
Last. Ruma BanerjeeH-Index: 86
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Abstract Although there is a growing recognition of the significance of hydrogen sulfide (H2S) as a biological signaling molecule involved in vascular and nervous system functions, its biogenesis and regulation are poorly understood. It is widely assumed that desulfhydration of cysteine is the major source of H2S in mammals and is catalyzed by the transsulfuration pathway enzymes, cystathionine β-synthase and cystathionine γ-lyase (CSE). In this study, we demonstrate that the profligacy of human...
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#1Karunakaran Venugopal (NU: Northeastern University)
#2Yuhan Sun (NU: Northeastern University)H-Index: 6
Last. Paul M. Champion (NU: Northeastern University)H-Index: 33
view all 7 authors...
Femtosecond coherence spectroscopy is used to study the low frequency dynamics of cystathionine beta-synthase (CBS). CBS is a pyridoxal-5′-phosphate-dependent heme enzyme with cysteine and histidine axial ligands that catalyzes the condensation of serine and homocysteine to form cystathionine. Resonance excitation near the maximum of the ferric state Soret band reveals a mode near ∼40 cm−1 (phase ∼pi/2). The phase indicates that the initial non-equilibrium coherent wavepacket for this mode is do...
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#2Peter Madzelan (NU: University of Nebraska–Lincoln)H-Index: 3
Covering: up to 2006Cystathionine β-synthase is a pyridoxal phosphate (PLP)-dependent hemeprotein, which catalyzes the condensation of serine and homocysteine to give cystathionine, the first step in the transsulfuration pathway. The association of heme with this enzyme in some organisms, including humans, is novel since this combination of cofactors has not been seen in any other protein to date. While the role of PLP in the reaction is suggested by the beta replacement reaction that is catalyz...
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