Investigation of Reaction Mechanism of Amino Acids and Phosphorus Trichloride by 31 P NMR and ESI-MS/MS

2011 ◽  
Vol 29 (6) ◽  
pp. 1173-1179 ◽  
Author(s):  
Yanchun Cao ◽  
Shuxia Cao ◽  
Yali Xie ◽  
Xiangkun Zong ◽  
Yufen Zhao
Keyword(s):  
Amino Acids ◽  
Reaction Mechanism ◽  
Phosphorus Trichloride ◽  
Esi Ms

scholarly journals Comparison of liver glycosylasparaginases from six vertebrates

1992 ◽  
Vol 282 (3) ◽  
pp. 891-897 ◽  
Author(s):  
O K Tollersrud ◽  
N N Aronson
Keyword(s):  
Amino Acids ◽  
Reaction Mechanism ◽  
Basic Structure ◽  
Low Ph ◽  
Beta Subunit ◽  
Beta Subunits ◽  
Species Identity ◽  
Closely Related Species ◽  
Human Enzyme ◽  
Specific Antisera

Structural and physical properties of glycosylasparaginase (EC 3.5.1.26) from the livers of human, pig, cow, rat, mouse and chicken were compared. The enzyme in all species had a common basic structure of two N-glycosylated subunits of about 24 (alpha) and 20 (beta) kDa joined by non-covalent forces. Subunit-specific antisera against the rat glycosylasparaginase bound specifically and sensitively to the corresponding subunits from all species. Identity of 80% of the amino acids was found between the N-terminal sequences of corresponding pig and rat glycosylasparaginase alpha- and beta-subunits and the deduced sequence from a human glycosylasparaginase cDNA [Fisher, Tollersrud & Aronson (1990) FEBS Lett. 269, 440-444]. The beta-subunit from all three species has an N-terminal threonine reported to be involved in the reaction mechanism for the human enzyme [Kaartinen, Williams, Tomich, Yates, Hood & Mononen (1991) J. Biol. Chem. 266, 5860-5869]. The native enzyme appeared as a heterodimer among the mammals, whereas the chicken enzyme had a greater molecular mass and is probably either a tetramer or a heterodimer bound to an unrelated peptide(s). All glycosylasparaginases were thermostable, requiring temperatures between 65 degrees C and 80 degrees C to be irreversibly inactivated. In addition, they were unusually stable at high pH and remained active in the presence of SDS except at low pH. The pH maximum was between 5.5 and 6 except for the rat and mouse enzymes which had a broad maximum between pH 7 and 8. A number of other properties were observed which also distinguish the enzyme from individual and closely related species.

scholarly journals Site-directed mutagenesis at aspartate and glutamate residues of xylanase from Bacillus pumilus

1992 ◽  
Vol 288 (1) ◽  
pp. 117-121 ◽  
Author(s):  
E P Ko ◽  
H Akatsuka ◽  
H Moriyama ◽  
A Shinmyo ◽  
Y Hata ◽  
...  
Keyword(s):  
Amino Acids ◽  
Reaction Mechanism ◽  
Amino Acid ◽  
Bacillus Pumilus ◽  
Specific Activity ◽  
Sequence Similarity ◽  
Site Directed Mutagenesis ◽  
Dimensional Structure ◽  
Amino Acid Sequence Similarity ◽  
Directed Mutagenesis

To elucidate the reaction mechanism of xylanase, the identification of amino acids essential for its catalysis is of importance. Studies have indicated the possibility that the reaction mechanism of xylanase is similar to that of hen's egg lysozyme, which involves acidic amino acid residues. On the basis of this assumption, together with the three-dimensional structure of Bacillus pumilus xylanase and its amino acid sequence similarity to other xylanases of different origins, three acidic amino acids, namely Asp-21, Glu-93 and Glu-182, were selected for site-directed mutagenesis. The Asp residue was altered to either Ser or Glu, and the Glu residues to Ser or Asp. The purified mutant xylanases D21E, D21S, E93D, E93S, E182D and E182S showed single protein bands of about 26 kDa on SDS/PAGE. C.d. spectra of these mutant enzymes show no effect on the secondary structure of xylanase, except that of D21E, which shows a little variation. Furthermore, mutations of Glu-93 and Glu-182 resulted in a drastic decrease in the specific activity of xylanase as compared with mutation of Asp-21. On the basis of these results we propose that Glu-93 and Glu-182 are the best candidates for the essential catalytic residues of xylanase.

Synthesis of 1-Alkyl-3-(2-oxo-2-aryl/alkyl-ethyl)indolin-2-ones through Gold/Brønsted Acid Relay Actions: Observation of Selective C=C Bond Cleavage of Enaminones

Synthesis ◽  
2017 ◽  
Vol 49 (16) ◽  
pp. 3609-3618 ◽  
Author(s):  
Yanzhong Li ◽  
Yulei Zhao ◽  
Yang Yuan ◽  
Lingkai Kong ◽  
Fangfang Zhang
Keyword(s):  
Reaction Mechanism ◽  
Bond Cleavage ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
One Pot ◽  
Esi Ms ◽  
Ms Analysis ◽  
Brönsted Acid

A novel gold(I)/Brønsted acid sequential catalyzed/promoted procedure to synthesize 1-alkyl-3-(2-oxo-2-aryl/alkyl-ethyl)indolin-2-ones under mild reaction conditions is developed. This methodology is realized by relay actions of gold and a Brønsted acid in a one-pot multistep manner. The gold(I)-catalyzed chemoselective C(sp2)-H functionalization of enaminones and Brønsted acid promoted cleavage of the C=C bond are integrated effectively. Based on the results of control experiments and ESI-MS analysis, a possible reaction mechanism is proposed.

Quantification of Underivatised Amino Acids on Dry Blood Spot, Plasma, and Urine by HPLC–ESI–MS/MS

2011 ◽  
pp. 219-242 ◽  
Author(s):  
Giuseppe Giordano ◽  
Iole Maria Di Gangi ◽  
Antonina Gucciardi ◽  
Mauro Naturale
Keyword(s):  
Amino Acids ◽  
Esi Ms ◽  
Blood Spot

The study of reaction mechanism for the transformation of nitronate into nitrile by phosphorus trichloride

Tetrahedron ◽  
2005 ◽  
Vol 61 (44) ◽  
pp. 10541-10551 ◽  
Author(s):  
Zhijay Tu ◽  
Yaochung Jang ◽  
Chunchi Lin ◽  
Ju-Tsung Liu ◽  
Jianming Hsu ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Phosphorus Trichloride

Towards a designed synthesis of metallic nanoparticles in polyols – elucidation of the redox scheme in a cobalt–ethylene glycol system

2016 ◽  
Vol 40 (10) ◽  
pp. 8632-8642 ◽  
Author(s):  
Kazuma Takahashi ◽  
Shun Yokoyama ◽  
Takatoshi Matsumoto ◽  
Jhon L. Cuya Huaman ◽  
Hisashi Kaneko ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Ethylene Glycol ◽  
Redox Reaction ◽  
Metallic Nanoparticles ◽  
Metal Particles ◽  
Esi Ms ◽  
System P ◽  
Ft Ir ◽  
Analytical Tools ◽  
Designed Synthesis

A new redox reaction mechanism in the formation of Co metal particles using an ethylene glycol–cobalt system is proposed using NMR, ESI-MS, FT-IR and XRD as analytical tools.

scholarly journals Mechanistic study on substitution reaction of a citrato(p-cymene)Ru(ii) complex with sulfur-containing amino acids

RSC Advances ◽  
2019 ◽  
Vol 9 (43) ◽  
pp. 25177-25183
Author(s):  
Sen-ichi Aizawa ◽  
Kohei Takizawa ◽  
Momoko Aitani
Keyword(s):  
Amino Acids ◽  
Reaction Mechanism ◽  
Kinetic Study ◽  
Substitution Reaction ◽  
Mechanistic Study ◽  
Sulfur Containing

Thorough kinetic study revealed characteristics of the reaction mechanism for arene ruthenium(ii) complexes with bio-related ligands.

scholarly journals Seasonal Variation of Mycosporine-Like Amino Acids in Three Subantarctic Red Seaweeds

Marine Drugs ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 75 ◽  
Author(s):  
Jocelyn Jofre ◽  
Paula S. M. Celis-Plá ◽  
Félix L. Figueroa ◽  
Nelso P. Navarro
Keyword(s):  
Amino Acids ◽  
High Resolution Mass Spectrometry ◽  
Marine Species ◽  
High Concentration ◽  
Red Seaweeds ◽  
Esi Ms ◽  
Corallina Officinalis ◽  
Different Seasons ◽  
Main Component ◽  
Composition I

UV-absorbing compounds, such as mycosporine-like amino acids (MAAs), are a group of secondary metabolites present in many marine species, including red seaweeds. In these organisms, the content and proportion of the composition of MAAs vary, depending on the species and several environmental factors. Its high cosmetic interest calls for research on the content and composition of MAAs, as well as the dynamics of MAAs accumulation in seaweeds from different latitudes. Therefore, this study aimed to survey the content of UV-absorbing MAAs in three Subantarctic red seaweeds during a seasonal cycle. Using spectrophotometric and HPLC techniques, the content and composition of MAAs of intertidal Iridaea tuberculosa, Nothogenia fastigiate, and Corallina officinalis were assessed. Some samples were also analyzed using high-resolution mass spectrometry coupled with HPLC-ESI-MS in order to identify more precisely the MAA composition. I. tuberculosa exhibited the highest MAA values (above 1 mg g−1 of dried mass weight), while C. officinalis showed values not exceeding 0.4 mg g−1. Porphyra-334 was the main component in N. fastigiata, whereas I. tuberculosa and C. officinalis exhibited a high content of palythine. Both content and composition of MAAs varied seasonally, with high concentration recorded in different seasons, depending on the species, i.e., winter (I. tuberculosa), spring (N. fastigiata), and summer (C. officinalis). HPLC-ESI-MS allowed us to identify seven different MAAs. Two were recorded for the first time in seaweeds from Subantarctic areas (mycosporine-glutamic acid and palythine-serine), and we also recorded an eighth UV-absorbing compound which remains unidentified.

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