Enzymic characterization of Bacillus subtilis GTP cyclohydrolase I. Evidence for a chemical dephosphorylation of dihydroneopterin triphosphate

1995 ◽  
Vol 306 (2) ◽  
pp. 371-377 ◽  
Author(s):  
A De Saizieu ◽  
P Vankan ◽  
A P GM van Loon
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Folic Acid ◽  
Physiological Role ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
Folate Biosynthesis

GTP cyclohydrolase I catalyses the first committing step in the biosynthesis of the pterin moiety of folic acid: conversion of GTP to dihydroneopterin triphosphate. GTP cyclohydrolase I of Bacillus subtilis was purified to homogeneity and shown to have a homo-octameric structure. The enzyme had an apparent Km for GTP of 4 microM and, in the absence of cations, a Vmax. of 80 nmol/min per mg of protein. K+ ions moderately increased its Vmax., whereas UTP and Ca2+ and Mg2+ ions drastically increased its Km for GTP. Dihydrofolate and other products of the folate and tetrahydrobiopterin pathways did not inhibit GTP cyclohydrolase I. In addition to their effect on the enzyme activity, Ca2+ and Mg2+ ions catalysed the chemical dephosphorylation of dihydroneopterin triphosphate to non-cyclic dihydroneopterin monophosphate, the substrate for the phosphomonoesterase reaction in folate biosynthesis. This dephosphorylation was specific and did not require the action of a phosphatase. We suggest a physiological role for Ca2+ ions and UTP in regulation of folate biosynthesis at the levels of GTP cyclohydrolase I and dephosphorylation of dihydroneopterin triphosphate.

IMMOBILIZATION OF AMYLASE PRODUCING BACTERIA (BACILLUS SUBTILIS) FROM SOIL OF WESTERN HIMALAYAN REGION SOLAN, HIMACHAL PRADESH, INDIA

2021 ◽  
pp. 109-115
Author(s):  
ARUN KUMAR ◽  
POONAM KUMARI ◽  
KASAHUN GUDETA ◽  
JM JULKA
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Physicochemical Properties ◽  
Bacterial Strain ◽  
Enzyme Activities ◽  
Enzyme Assay ◽  
Himachal Pradesh ◽  
Genus Bacillus ◽  
Western Himalayan Region

Objective: The paper aimed to immobilize amylase producing bacterial strain on a suitable matrix and characterization of its physicochemical properties so that much amount of amylase could be produced to be applied in different industries. Methods: Bacterial colonies were sub-cultured from samples collected from soil in freshly prepared dishes containing starch agar by dot method using sterile inoculating needles from which five different bacteria belonged to genus Bacillus were isolated and assigned as A1, A2, A3, A4, and A5. Results: It was found that A1 displayed the highest enzyme activity of 17.89 IU/ml with enzyme assay of 0.83 mg/ml and the bacterium was identified to be Bacillus subtilis. A5 displayed 10.13 IU/ml with protein contents of 0.11 mg/ml indicated that A1 possess the highest enzyme activities which were categorized under Bacillus and protein contents and A5 showed less amount of enzyme activities and protein contents as compared to other. Conclusion: The bacteria which were produced much amount of enzyme activities identified as Bacillus subtilis and recommended and have been recommended to be cultured for the production of amylase enzyme.

Molecular Characterization of HPH-1: A Mouse Mutant Deficient in GTP Cyclohydrolase I Activity

1994 ◽  
Vol 203 (3) ◽  
pp. 1675-1681 ◽  
Author(s):  
M. Gutlich ◽  
I. Ziegler ◽  
K. Witter ◽  
B. Hemmens ◽  
L. Hultner ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Mouse Mutant ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase

Crystallization and preliminary crystallographic characterization of GTP cyclohydrolase I from Escherichia coli

1992 ◽  
Vol 226 (4) ◽  
pp. 1279-1281 ◽  
Author(s):  
Cornelia Schmid ◽  
Rudolf Ladenstein ◽  
Hartmut Luecke ◽  
Robert Huber ◽  
Adelbert Bacher
Keyword(s):  
Escherichia Coli ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase

scholarly journals YtsJ Has the Major Physiological Role of the Four Paralogous Malic Enzyme Isoforms in Bacillus subtilis

2006 ◽  
Vol 188 (13) ◽  
pp. 4727-4736 ◽  
Author(s):  
Guillaume Lerondel ◽  
Thierry Doan ◽  
Nicola Zamboni ◽  
Uwe Sauer ◽  
Stéphane Aymerich
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Malic Enzyme ◽  
Metabolic Flux ◽  
Physiological Role ◽  
Extreme Case ◽  
Growth Defect ◽  
Flux Analysis ◽  
Malic Enzyme Activity

ABSTRACT The Bacillus subtilis genome contains several sets of paralogs. An extreme case is the four putative malic enzyme genes maeA, malS, ytsJ, and mleA. maeA was demonstrated to encode malic enzyme activity, to be inducible by malate, but also to be dispensable for growth on malate. We report systematic experiments to test whether these four genes ensure backup or cover different functions. Analysis of single- and multiple-mutant strains demonstrated that ytsJ has a major physiological role in malate utilization for which none of the other three genes could compensate. In contrast, maeA, malS, and mleA had distinct roles in malate utilization for which they could compensate one another. The four proteins exhibited malic enzyme activity; MalS, MleA, and MaeA exhibited 4- to 90-fold higher activities with NAD+ than with NADP+. YtsJ activity, in contrast, was 70-fold higher with NADP+ than with NAD+, with Km values of 0.055 and 2.8 mM, respectively. lacZ fusions revealed strong transcription of ytsJ, twofold higher in malate than in glucose medium, but weak transcription of malS and mleA. In contrast, mleA was strongly transcribed in complex medium. Metabolic flux analysis confirmed the major role of YtsJ in malate-to-pyruvate interconversion. While overexpression of the NADP-dependent Escherichia coli malic enzyme MaeB did not suppress the growth defect of a ytsJ mutant on malate, overexpression of the transhydrogenase UdhA from E. coli partially suppressed it. These results suggest an additional physiological role of YtsJ beyond that of malate-to-pyruvate conversion.

Characterization of transgenic mice with the expression of phenylalanine hydroxylase and GTP cyclohydrolase I in the skin

2005 ◽  
Vol 14 (7) ◽  
pp. 535-542 ◽  
Author(s):  
Rikke Christensen ◽  
Leena Alhonen ◽  
Jarmo Wahlfors ◽  
Maria Jakobsen ◽  
Thomas G. Jensen
Keyword(s):  
Transgenic Mice ◽  
Phenylalanine Hydroxylase ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase

scholarly journals Characterization of Mouse and Human GTP Cyclohydrolase I Genes

1995 ◽  
Vol 270 (17) ◽  
pp. 10062-10071 ◽  
Author(s):  
Hiroshi Ichinose ◽  
Tamae Ohye ◽  
Yoichi Matsuda ◽  
Tada-aki Hori ◽  
Nenad Blau ◽  
...  
Keyword(s):  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase
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