Institution
National Chemical Laboratory
Facility•Pune, Maharashtra, India•
About: National Chemical Laboratory is a facility organization based out in Pune, Maharashtra, India. It is known for research contribution in the topics: Catalysis & Nanoparticle. The organization has 8891 authors who have published 14837 publications receiving 387600 citations.
Papers published on a yearly basis
Papers
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TL;DR: Very active, selective, and efficient Ni/MgO catalysts were used to convert methane at relatively low temperatures (300-700 °C) to H 2 and CO in the molar ratio 2:1.
Abstract: Very active, selective, and efficient-a Ni/MgO catalyst converts methane at relatively low temperatures (300-700 °C) to H 2 and CO in the molar ratio 2:1 The high activity of the catalyst makes it possible to operate at high space velocities (low contact times) and therefore in the region of kinetic control for the selectivity
109 citations
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TL;DR: In this paper, a variety of aldehydes react with acetic anhydride in the presence of catalytic amount of β zeolite to afford the corresponding 1,1 diacetates in good to excellent yields.
109 citations
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TL;DR: The crystal structure of PVA was determined to establish the nature of its catalytic mechanism and to identify any biochemical and structural relationships with PGA and other Ntn (N-terminal nucleophile) hydrolases.
Abstract: 414 nature structural biology ¥ volume 6 number 5 ¥ may 1999 Two enzyme types, penicillin V acylases (PVA) and penicillin G acylases (PGA), with distinct substrate preferences, account for all the enzymic industrial production of 6-aminopenicillanic acid 1,2. This b-lactam compound is then elaborated into a range of semi-synthetic penicillins. Although their industrial substrates are very similar, representative examples of the two enzyme types differ widely in molecular properties. PVA from Bacillus sphaericus is tetrameric with a monomer M r of 35,000 while PGA from Escherichia coli is a heterodimer of M r 90,000. Furthermore, they have no detectable sequence homology. These differences, which exist in spite of the similarity of their industrial substrates, provoked us to determine the crystal structure of PVA to establish the nature of its catalytic mechanism and to identify any biochemical and structural relationships with PGA and other Ntn (N-terminal nucleophile) hydrolases. The PVA molecule is a well-defined tetramer with 222 organization made up of two obvious dimers (A and D) and (B and C), which generate a flat disc-like assembly (Fig. 1a). The X-ray analysis revealed that the PVA monomer contains two central anti-parallel b-sheets above and below which is a pair of anti-parallel helices (Fig. 1b). There are two extensions , one from the upper pair of helices and the other at the C-terminal segment, that interact with other monomers in the tetramer and help stabilize it. The b-sheet and helix organization and connectivity are characteristic of members of the Ntn hydrolase family, which have an N-terminal catalytic residue that is often created by autocatalytic processing 3,4. In the PVA structure, cysteine was observed as the N-terminal residue, whereas the gene sequence predicts an N-terminal sequence of Met-Leu-Gly-Cys 5. This finding shows that three amino acids are processed from the precursor N-terminus to unmask a nucleophile with a free a-amino group. Since PVA is an Ntn hydro-lase, we can deduce that the N-terminal cysteine in PVA is the catalytic residue. The PVA and PGA enzymes thus share a distinctive structural core but are otherwise unrelated in primary sequence, including the active site residue. Both PGA and PVA have approximately the same angle (+30°) between the b-strands of the two b-sheets, which are decorated by the active site residues in Ntn hydro-lases. Using these b-sheets for structural alignment reveals that the catalytic regions of PVA and PGA overlap (Fig. 1c) with a root …
109 citations
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TL;DR: Proton conductivity has been studied thoroughly in two isomeric In(III)-isophthalate based MOFs and it is shown that In-IA-2D-2 can conduct protons under humidified as well as anhydrous conditions.
109 citations
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TL;DR: In this paper, a highly efficient and facile method for the synthesis of substituted 2-aminothiazoles in water without any added catalyst or co-organic solvent was described, which was successfully applied for the preparation of an anti-inflammatory drug, fanetizole.
109 citations
Authors
Showing all 8913 results
Name | H-index | Papers | Citations |
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Ashok Kumar | 151 | 5654 | 164086 |
Rajesh Kumar | 149 | 4439 | 140830 |
Tak W. Mak | 148 | 807 | 94871 |
John T. O'Brien | 121 | 819 | 63242 |
Clive Ballard | 117 | 736 | 61663 |
Yoshinori Tokura | 117 | 858 | 70258 |
John S. Mattick | 116 | 367 | 64315 |
Michael Dean | 107 | 419 | 63335 |
Ian G. McKeith | 107 | 468 | 51954 |
David J. Burn | 100 | 446 | 39120 |
Anil Kumar | 99 | 2124 | 64825 |
Vikas Kumar | 89 | 859 | 39185 |
Detlef W. Bahnemann | 88 | 517 | 48826 |
Gautam R. Desiraju | 88 | 458 | 45301 |
Praveen Kumar | 88 | 1339 | 35718 |