scholarly journals His151 and His296 Are the Acid-Base Catalytic Residues of Bacillus cereus Sphingomyelinase in Sphingomyelin Hydrolysis

2003 ◽  
Vol 26 (7) ◽  
pp. 920-926 ◽  
Author(s):  
Takashi Obama ◽  
Shinobu Fujii ◽  
Hiroh Ikezawa ◽  
Kiyoshi Ikeda ◽  
Masayoshi Imagawa ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Acid Base ◽  
Catalytic Residues

scholarly journals Identification of Acid-Base Catalytic Residues of High-MrThioredoxin Reductase fromPlasmodium falciparum

2006 ◽  
Vol 281 (44) ◽  
pp. 32967-32977 ◽  
Author(s):  
Paul J. McMillan ◽  
L. David Arscott ◽  
David P. Ballou ◽  
Katja Becker ◽  
Charles H. Williams ◽  
...  
Keyword(s):  
Acid Base ◽  
Catalytic Residues

Cross-functionalities of Bacillus deacetylases involved in bacillithiol biosynthesis and bacillithiol-S-conjugate detoxification pathways

2013 ◽  
Vol 454 (2) ◽  
pp. 239-247 ◽  
Author(s):  
Zhong Fang ◽  
Alexandra A. Roberts ◽  
Karissa Weidman ◽  
Sunil V. Sharma ◽  
Al Claiborne ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Bacillus Anthracis ◽  
Kinetic Analysis ◽  
Genomic Analysis ◽  
Activity Profile ◽  
Acid Base ◽  
Key Enzyme ◽  
Acetyl Group ◽  
High Degree ◽  
Detoxification Pathways

BshB, a key enzyme in bacillithiol biosynthesis, hydrolyses the acetyl group from N-acetylglucosamine malate to generate glucosamine malate. In Bacillus anthracis, BA1557 has been identified as the N-acetylglucosamine malate deacetylase (BshB); however, a high content of bacillithiol (~70%) was still observed in the B. anthracis ∆BA1557 strain. Genomic analysis led to the proposal that another deacetylase could exhibit cross-functionality in bacillithiol biosynthesis. In the present study, BA1557, its paralogue BA3888 and orthologous Bacillus cereus enzymes BC1534 and BC3461 have been characterized for their deacetylase activity towards N-acetylglucosamine malate, thus providing biochemical evidence for this proposal. In addition, the involvement of deacetylase enzymes is also expected in bacillithiol-detoxifying pathways through formation of S-mercapturic adducts. The kinetic analysis of bacillithiol-S-bimane conjugate favours the involvement of BA3888 as the B. anthracis bacillithiol-S-conjugate amidase (Bca). The high degree of specificity of this group of enzymes for its physiological substrate, along with their similar pH–activity profile and Zn2+-dependent catalytic acid–base reaction provides further evidence for their cross-functionalities.

scholarly journals Crystal Structures of Streptomyces Coelicolor Methylmalonyl-CoA Epimerase with Substrate or Transition State Analog Contradicts a Simple General Acid-Base Catalytic Mechanism

2021 ◽  
Author(s):  
Lee M Stunkard ◽  
Aaron B Benjamin ◽  
James Bower ◽  
Tyler Huth ◽  
Jeremy Lohman
Keyword(s):  
Transition State ◽  
Crystal Structures ◽  
Conformational Changes ◽  
Catalytic Mechanism ◽  
Streptomyces Coelicolor ◽  
Base Catalysis ◽  
Acid Base ◽  
Transition State Analog ◽  
Catalytic Residues ◽  
General Acid

Crystal structures of Streptomyces coelicolor methylmalonyl-CoA epimerase in the holo-form, with substrate or the putative transition state analog, 2-nitroproionyl-CoA. The proposed catalytic mechanism is general acid-base catalysis. The proposed catalytic residues are too far from the substrate or analog, unless conformational changes take place or some other mechanism is used. <br>

scholarly journals Evidence in Support of Lysine 77 and Histidine 96 as Acid–Base Catalytic Residues in Saccharopine Dehydrogenase from Saccharomyces cerevisiae

Biochemistry ◽  
2012 ◽  
Vol 51 (4) ◽  
pp. 857-866 ◽  
Author(s):  
Vidya Prasanna Kumar ◽  
Leonard M. Thomas ◽  
Kostyantyn D. Bobyk ◽  
Babak Andi ◽  
Paul F. Cook ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acid Base ◽  
Catalytic Residues ◽  
Saccharopine Dehydrogenase

scholarly journals Crystal Structures of Streptomyces Coelicolor Methylmalonyl-CoA Epimerase with Substrate or Transition State Analog Contradicts a Simple General Acid-Base Catalytic Mechanism

2021 ◽  
Author(s):  
Lee M Stunkard ◽  
Aaron B Benjamin ◽  
James Bower ◽  
Tyler Huth ◽  
Jeremy Lohman
Keyword(s):  
Transition State ◽  
Crystal Structures ◽  
Conformational Changes ◽  
Catalytic Mechanism ◽  
Streptomyces Coelicolor ◽  
Base Catalysis ◽  
Acid Base ◽  
Transition State Analog ◽  
Catalytic Residues ◽  
General Acid

Crystal structures of Streptomyces coelicolor methylmalonyl-CoA epimerase in the holo-form, with substrate or the putative transition state analog, 2-nitroproionyl-CoA. The proposed catalytic mechanism is general acid-base catalysis. The proposed catalytic residues are too far from the substrate or analog, unless conformational changes take place or some other mechanism is used. <br>

Higher Dietary Acidity is Associated with Lower Bone Mineral Density in Postmenopausal Iranian Women, Independent of Dietary Calcium Intake

2014 ◽  
Vol 84 (3-4) ◽  
pp. 0206-0217 ◽  
Author(s):  
Seyedeh-Elaheh Shariati-Bafghi ◽  
Elaheh Nosrat-Mirshekarlou ◽  
Mohsen Karamati ◽  
Bahram Rashidkhani
Keyword(s):  
Calcium Intake ◽  
Dietary Calcium ◽  
Dietary Calcium Intake ◽  
Dietary Intakes ◽  
Iranian Women ◽  
Acid Base Balance ◽  
Mineral Density ◽  
Acid Base ◽  
Base Balance ◽  
Dietary Acid

Findings of studies on the link between dietary acid-base balance and bone mass are relatively mixed. We examined the association between dietary acid-base balance and bone mineral density (BMD) in a sample of Iranian women, hypothesizing that a higher dietary acidity would be inversely associated with BMD, even when dietary calcium intake is adequate. In this cross-sectional study, lumbar spine and femoral neck BMDs of 151 postmenopausal women aged 50 - 85 years were measured using dual-energy x-ray absorptiometry. Dietary intakes were assessed using a validated food frequency questionnaire. Renal net acid excretion (RNAE), an estimate of acid-base balance, was then calculated indirectly from the diet using the formulae of Remer (based on dietary intakes of protein, phosphorus, potassium, and magnesium; RNAERemer) and Frassetto (based on dietary intakes of protein and potassium; RNAEFrassetto), and was energy adjusted by the residual method. After adjusting for potential confounders, multivariable adjusted means of the lumbar spine BMD of women in the highest tertiles of RNAERemer and RNAEFrassetto were significantly lower than those in the lowest tertiles (for RNAERemer: mean difference -0.084 g/cm2; P=0.007 and for RNAEFrassetto: mean difference - 0.088 g/cm2; P=0.004). Similar results were observed in a subgroup analysis of subjects with dietary calcium intake of >800 mg/day. In conclusion, a higher RNAE (i. e. more dietary acidity), which is associated with greater intake of acid-generating foods and lower intake of alkali-generating foods, may be involved in deteriorating the bone health of postmenopausal Iranian women, even in the context of adequate dietary calcium intake.

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