TAILIEUCHUNG - Báo cáo khoa học: UDP-galactose 4-epimerase from Kluyveromyces fragilis – catalytic sites of the homodimeric enzyme are functional and regulated

UDP-galactose 4-epimerase fromKluyveromyces fragilisis a homodimer containing one catalytic site and one NAD + as cofactor per subunit. One 5¢-UMP, a competitive inhibitor, binds per dimer of epimerase as isolated and causes inactivation. Addition of mminhibitor to the enzyme in vitro leads to three sequential steps: first, the inhibitor binds to the unoccupied site; second, the inhibitor bound ex vivo is displaced allosterically; and finally, both sites are occupied by the inhibitor. | ỊFEBS Journal UDP-galactose 4-epimerase from Kluyveromyces fragilis - catalytic sites of the homodimeric enzyme are functional and regulated Amrita Brahma Nupur Banerjee and Debasish Bhattacharyya StructuralBiology and Bioinformatics Division Indian Institute of ChemicalBiology CSIR Jadavpur Kolkata India Keywords catalytic sites inhibitor multimeric enzyme regulation UDP-galactose 4-epimerase Correspondence D. Bhattacharyya StructuralBiology and Bioinformatics Division Indian Institute of ChemicalBiology CSIR 4 Raja S. C. Mallick Road Jadavpur Kolkata 700 032 India Fax 91 33 2473 5197 0284 Tel 91 33 2499 5764 E-mail debasish@ These authors contributed equally to this work Received 20 July 2009 revised 20 August 2009 accepted 16 September 2009 doi UDP-galactose 4-epimerase from Kluyveromyces fragilis is a homodimer containing one catalytic site and one NAD as cofactor per subunit. One 5 -UMP a competitive inhibitor binds per dimer of epimerase as isolated and causes inactivation. Addition of mM inhibitor to the enzyme in vitro leads to three sequential steps first the inhibitor binds to the unoccupied site second the inhibitor bound ex vivo is displaced allosterically and finally both sites are occupied by the inhibitor. These reactions have been monitored by kinetic lag in substrate conversion coenzyme fluorescence protection against trypsin digestion and reductive inhibition. The transition profiles indicate the existence of a stable intermediate with one inhibitor-binding site remaining unoccupied. Reductive inhibition of this intermediate reduced the activity to 58 2 with modification of one catalytic site. A change of conformation of the epimerase upon binding with substrate or inhibitor was evident from fluorescence emission spectra. The epimerase demonstrated a biphasic Michaelis-Menten dependency. The epimerase devoid of 5 -UMP showed a Michaelis-Menten dependency that can be explained by assuming simultaneous

• Báo cáo khoa học
• scientific reports
• thesis report
• medical report
• Structural biochemistry
• bacteria
• chemical reaction
• collection of scientific reports
• industry reports philosophy of history reports
• reports in literature
• a scientific b shirt
• presentation of scientific reports
• reports on literature
• philosophy statement
• documents
• studies English language and English language communication and English language commercial
• progress reports at scientific collections
• agronomic reports
• reports in physics
• biology reports
• thematic biological
• induced geometry
• mathematical topics
• quantum mechanics
• physics
• reporting mathematics
• physics reports
• livestock reports
• physical reports
• research physicist
• specializing in physics
• mathematical statements
• mathematical equations
• English pronunciation
• presentation report
• agricultural reports
• technical crops
• bio technology
• English reports
• scientific research
• presentation reports
• mathematical knowledge
• reports of mathematics
• represented
• Wilf on packing distinct
• Tur´n density
• mathematical works
• patterns in a permutation
• statements and documents scientific reports
• reports agronomy
• biotechnology
• plants Vietnam
• specialized biological
• microbiological methods
• presenting the report
• anti bacterial properties of shrimp
• energy exchange
• engineering chicken
• Path counting
• random matrix theory
• Even circuits
• prescribed clockwise parity
• Correspondence between
• algorithmic characterizations
• Finding Induced Acyclic
• Random Digraphs
• Nonexistence results
• Hadamard like matrices
• Voltage Graphs
• Group Presentations
• Cages mathematical knowledge
• Dominance Order
• Graphical Partitions
• On the functions
• values in [α(G
• Box With Translates
• Two Given Rectangular Brick
• On the q analogue
• the sum of cubes