scholarly journals Photoaffinity labelling of human poly(ADP-ribose) polymerase catalytic domain

1997 ◽  
Vol 322 (2) ◽  
pp. 469-475 ◽  
Author(s):  
Hyuntae KIM ◽  
Myron K. JACOBSON ◽  
Véronique ROLLI ◽  
Josiane MÉNISSIER-de MURCIA ◽  
Joseph REINBOLT ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Insertion Site ◽  
Site Directed Mutagenesis ◽  
Crystallographic Structure ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Photoaffinity Labelling ◽  
Adenine Ring ◽  
Boronate Affinity Chromatography ◽  
Binding Residues

Photoaffinity labelling of the human poly(ADP-ribose) polymerase (PARP) catalytic domain (40 kDa) with the NAD+ photoaffinity analogue 2-azido-[α-32P]NAD+ has been used to identify NAD+-binding residues. In the presence of UV, photoinsertion of the analogue was observed with a stoichiometry of 0.73 mol of 2-azido-[α-32P]NAD+ per mol of catalytic domain. Competition experiments indicated that 3-aminobenzamide strongly protected the insertion site. Residues binding the adenine ring of NAD+ were identified by trypsin digestion and boronate affinity chromatography in combination with reverse-phase HPLC. Two major NAD+-binding residues, Trp1014 of peptide Thr1011–Trp1014 and Lys893 of peptide Ile879 –Lys893, were identified. The site-directed mutagenesis of these two residues revealed that Lys893, but not Trp1014, is critical for activity. The close positioning of Lys893 near the adenine ring of NAD+ has been confirmed by the recently solved crystallographic structure of the chicken PARP catalytic domain [Ruf, Ménissier-de Murcia, de Murcia and Schulz (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 7481–7485].

scholarly journals Crystal Structures of Yeast β-Alanine Synthase Complexes Reveal the Mode of Substrate Binding and Large Scale Domain Closure Movements

2007 ◽  
Vol 282 (49) ◽  
pp. 36037-36047 ◽  
Author(s):  
Stina Lundgren ◽  
Birgit Andersen ◽  
Jure Piškur ◽  
Doreen Dobritzsch
Keyword(s):  
Crystal Structures ◽  
Large Scale ◽  
Catalytic Domain ◽  
Substrate Binding ◽  
Salt Bridge ◽  
Site Directed Mutagenesis ◽  
Wild Type ◽  
Dimerization Domain ◽  
Binding Residues ◽  
Present Site

β-Alanine synthase is the final enzyme of the reductive pyrimidine catabolic pathway, which is responsible for the breakdown of uracil and thymine in higher organisms. The fold of the homodimeric enzyme from the yeast Saccharomyces kluyveri identifies it as a member of the AcyI/M20 family of metallopeptidases. Its subunit consists of a catalytic domain harboring a di-zinc center and a smaller dimerization domain. The present site-directed mutagenesis studies identify Glu159 and Arg322 as crucial for catalysis and His262 and His397 as functionally important but not essential. We determined the crystal structures of wild-type β-alanine synthase in complex with the reaction product β-alanine, and of the mutant E159A with the substrate N-carbamyl-β-alanine, revealing the closed state of a dimeric AcyI/M20 metallopeptidase-like enzyme. Subunit closure is achieved by a ∼30° rigid body domain rotation, which completes the active site by integration of substrate binding residues that belong to the dimerization domain of the same or the partner subunit. Substrate binding is achieved via a salt bridge, a number of hydrogen bonds, and coordination to one of the zinc ions of the di-metal center.

Characterization of Recombinant Human Coagulation Factor XFriuli

1996 ◽  
Vol 75 (02) ◽  
pp. 313-317 ◽  
Author(s):  
D J Kim ◽  
A Girolami ◽  
H L James
Keyword(s):  
Catalytic Domain ◽  
Coagulation Factor ◽  
Molecular Size ◽  
Binding Pocket ◽  
Site Directed Mutagenesis ◽  
Bleeding Tendency ◽  
Factor X ◽  
Amino Terminal ◽  
Normal Plasma ◽  
Plasma Factor

SummaryNaturally occurring plasma factor XFriuli (pFXFr) is marginally activated by both the extrinsic and intrinsic coagulation pathways and has impaired catalytic potential. These studies were initiated to obtain confirmation that this molecule is multi-functionally defective due to the substitution of Ser for Pro at position 343 in the catalytic domain. By the Nelson-Long site-directed mutagenesis procedure a construct of cDNA in pRc/CMV was derived for recombinant factor XFriuli (rFXFr) produced in human embryonic (293) kidney cells. The rFXFr was purified and shown to have a molecular size identical to that of normal plasma factor X (pFX) by gel electrophoretic, and amino-terminal sequencing revealed normal processing cleavages. Using recombinant normal plasma factor X (rFXN) as a reference, the post-translational y-carboxy-glutamic acid (Gla) and (β-hydroxy aspartic acid (β-OH-Asp) content of rFXFr was over 85% and close to 100%, respectively, of expected levels. The specific activities of rFXFr in activation and catalytic assays were the same as those of pFXFr. Molecular modeling suggested the involvement of a new H-bond between the side-chains of Ser-343 and Thr-318 as they occur in anti-parallel (3-pleated sheets near the substrate-binding pocket of pFXFr. These results support the conclusion that the observed mutation in pFXFr is responsible for its dysfunctional activation and catalytic potentials, and that it accounts for the moderate bleeding tendency in the homozygous individuals who possess this variant procoagulant.

Understanding Process Variables and their Interactions for Maximizing Production of Artemisinin Derivative Artemether (Anti-Malarial Drug) Through Cunninghamella echinulata var elegans at 5 L Bioreactor Level

2019 ◽  
Vol 15 (4) ◽  
pp. 442-452
Author(s):  
Kashyap Kumar Dubey ◽  
Punit Kumar
Keyword(s):  
Experimental Finding ◽  
Culture Broth ◽  
Quadratic Model ◽  
Optimum Conditions ◽  
Reverse Phase Hplc ◽  
Polar Solvents ◽  
Reverse Phase ◽  
Experimental Conditions ◽  
Cunninghamella Echinulata ◽  
Life Threatening

Background: Malaria is one of the life threatening diseases which is caused by Plasmodium sp. of protozoa and uses Anopheles mosquitos as vector. Plasmodium vivax and Plasmodium falciparum are common form of malaria parasite. Artemisinin is reported for its antimalarial activities and Artemether which is a methyl ether derivative of Artemisinin, has been found effective against P. falciparum. Methods: In the present study, bioconversion of Artemisinin into Artemether was carried out experimentally and the statistical tools like experimental factorial design and Response Surface Methodology were used to find optimal conditions (concentration of Artemisinin, age of inoculum, temperature & pH) using Cunninghamella echinulata var. elegans. Experimental conditions for maximum product recovery from culture broth were also optimized using various polar and non-polar solvents for extraction. Artemether purity was analyzed by reverse-phase HPLC. Experimental data was fitted in a quadratic model and effect of various parameters was analyzed. Results: It was found that bioconversion of Artemisinin into Artemether is growth associated process. It was observed that molasses used as carbon source supported production of Artemether to 3.4g/L. The biomass and oxygen are key element affecting of bioconversion of Artemisinin into Artemether such as higher dissolved oxygen reduced the Artemether bioconversion. The highest bioconversion of Artemisinin into Artemether was obtained at temperature 25.5oC, 5g/L concentration of Artemisinin, at age of inoculum of 44.5 h and at pH 6.0. Model suggested the highest bioconversion of Artemisinin into Artemether was 54% at shake flask level which was near about experimental finding. An optimal condition for bioconversion was also analyzed and 64% bioconversion was obtained in 5L bioreactor. Conclusion: The outcomes of the study provided optimum conditions for bioconversion of Artemisinin into Artemether.

scholarly journals Orphan Designation and Cisplatin/Hyaluronan Complex in an Intracavitary Film for Malignant Mesothelioma

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 362
Author(s):  
Sabrina Banella ◽  
Eride Quarta ◽  
Paolo Colombo ◽  
Fabio Sonvico ◽  
Antonella Pagnoni ◽  
...  
Keyword(s):  
Sodium Hyaluronate ◽  
Chloride Ions ◽  
Complete Resection ◽  
Size Exclusion ◽  
European Medicines Agency ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Pharmaceutical Development ◽  
Film Forming ◽  
Exclusion Chromatography

Pleural mesothelioma is a lung diffuse tumor, whose complete resection is unlikely. Consequently, metastases reappear where the primary tumor was removed. This paper illustrates the orphan medicine designation procedure of an intracavitary cisplatin film and related pharmaceutical development aspects requested by the European Medicines Agency (EMA) in its Scientific Advice. Since cisplatin pharmacokinetics from the implanted film in sheep resulted substantially modified compared to intravenous administration, the formation of a cisplatin/hyaluronan complex had been hypothesized. Here, the interaction between sodium hyaluronate (NaHA) and cisplatin (CisPt) was demonstrated. Size exclusion chromatography qualitatively evidenced the complex in the film-forming mixture, only showing the NaHA peak. Atomic absorption spectroscopy of the corresponding fraction revealed platinum, confirming the interaction. Reverse phase HPLC quantified about 5% free cisplatin in the film-forming mixture, indirectly meaning that 95% was complexed. Finally, a study of CisPt release from the film assessed how CisPt/NaHA complex affected drug availability. In water, a medium without chloride ions, there was no release and the film remained intact for 48 h and longer, whereas the placebo film dissolved in 15 min. In 0.9% NaCl medium, the film became more soluble, dissolving within 3–4 h. However, cisplatin release was still controlled by the existing complex in solution until chloride ions displaced it. While the film modified its dissolution with aging, CisPt release remained unaffected (90% released in 48 h).

Quantitation of Amiodarone and Desethylamiodarone from Blood Serum and Myocardium Using Reverse Phase HPLC

1987 ◽  
Vol 10 (12) ◽  
pp. 2625-2637 ◽  
Author(s):  
J. Alan Menius ◽  
D. James Schumacher ◽  
Emily A. Hull-ryde ◽  
Cyril Y. Leung ◽  
Robin G. Cummings ◽  
...  
Keyword(s):  
Blood Serum ◽  
Reverse Phase Hplc ◽  
Reverse Phase

In vitro 19-norandrogen synthesis by equine placenta requires the participation of aromatase

1995 ◽  
Vol 144 (3) ◽  
pp. 517-525 ◽  
Author(s):  
S Moslemi ◽  
P Silberzahn ◽  
J-L Gaillard
Keyword(s):  
Silica Gel ◽  
Aromatase Inhibitors ◽  
Column Chromatography ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Term Placenta ◽  
Flow Detector

Abstract Explants of equine full-term placenta have been shown to synthesize 19-norandrogens from labelled androgens. Steroid metabolites were purified by silica-gel column chromatography then analysed and quantified by C18-reverse-phase HPLC coupled to a radioactive flow detector. 19-Norandrostenedione was subsequently recrystallized to constant specific activity, providing unequivocal evidence of its synthesis by the equine placenta. 19-Norandrostenedione synthesis appeared to be localized in the microsomal fraction. Regardless of the substrate used, formation of 19-norandrogens was far weaker than that of oestrogens; moreover, the yield of 17-oxosteroids produced was much greater than that of 17β-hydroxysteroids, suggesting the presence of a dehydrogenase with predominant oxidative activity. Sulphoconjugated steroids formed were less than 0·5% of total steroids. Although 19-nortestosterone could not be generated by equine purified aromatase incubated with labelled testosterone, the synthesis of 19-norandrogens and oestrogens by equine placental explants was blocked by two specific aromatase inhibitors, 4-hydroxyandrostenedione and fadrozole. Our results provide evidence for a placental origin of at least a part of the 19-norandrogens previously identified in the blood of the pregnant mare. Furthermore, it is suggested that 19-norandrogen biosynthesis would involve the enzymatic metabolism of 19-oxygenated androgens formed by equine aromatase. Journal of Endocrinology (1995) 144, 517–525

scholarly journals RP-HPLC Determination of Raloxifene in Pharmaceuticl Tablets

2006 ◽  
Vol 3 (1) ◽  
pp. 60-64 ◽  
Author(s):  
P. Venkata Reddy ◽  
B. Sudha Rani ◽  
G. Srinu Babu ◽  
J. V. L. N. Seshagiri Rao
Keyword(s):  
Flow Rate ◽  
Retention Time ◽  
Mobile Phase ◽  
Dosage Forms ◽  
Hplc Method ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Pharmaceutical Dosage Forms ◽  
Rp Hplc

A reverse phase HPLC method is developed for the determination of Raloxifene in pharmaceutical dosage forms. Chromatography was carried out on an inertsil C18 column using a mixture of acetonitrile and phosphate buffer (30:70 v/v) as the mobile phase at a flow rate of 1 mL/min. Detection was carried out at 290 nm .The retention time of the drug was 10.609 min. The method produced linear responses in the concentration range of 0.5-200 µg/mL of Raloxifene. The method was found to be applicable for determination of the drug in tablets.

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