scholarly journals High yield and high specific activity synthesis of [18F]fallypride in a batch microfluidic reactor for micro-PET imaging

2014 ◽  
Vol 50 (10) ◽  
pp. 1192-1194 ◽  
Author(s):  
Muhammad Rashed Javed ◽  
Supin Chen ◽  
Jack Lei ◽  
Jeffrey Collins ◽  
Maxim Sergeev ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Specific Activity ◽  
High Specific Activity ◽  
High Yield ◽  
Microfluidic Reactor

Synthesis and N.M.R. Spectra of Substituted Aminoiodoacridines

1979 ◽  
Vol 32 (12) ◽  
pp. 2637 ◽  
Author(s):  
RF Martin ◽  
DP Kelly
Keyword(s):  
Electron Density ◽  
Electrophilic Substitution ◽  
Specific Activity ◽  
Diazonium Salt ◽  
High Specific Activity ◽  
High Yield ◽  
Model Compounds ◽  
Iodide Ion ◽  
Ion Substitution ◽  
Chloramine T

3-Amino-6-iodoacridine (10), 3,6-diiodoacridine (11) and 9-amino-2-ethoxy-6-iodoacridine (14) were prepared by iodide ion substitution of the corresponding diazonium salt whereas 3,6-diamino-4,5-diiodoacridine (12) and 6,9-diamino-2-ethoxy-5-iodoacridine (13) were prepared by direct iodination with iodide ion in the presence of chloramine-T. The latter reaction proceeded in relatively high yield and has been used for the synthesis of high specific activity 125I-labelled compounds (12), (13). The 1H and 13C N.M.R. spectra of (10)-(14) and model compounds indicate higher electron density at C4(C5) than at C2(C7) in 3(6)-amino-substituted acridines in agreement with the observed pattern of electrophilic substitution.

Preparation of 14C-Labeled Penicillic Acid with High Specific Activity and Yield

1977 ◽  
Vol 40 (2) ◽  
pp. 90-93 ◽  
Author(s):  
DOUGLAS L. PARK ◽  
PHILIP B. MISLIVEC ◽  
JAMES L. HEATH
Keyword(s):  
Acid Production ◽  
Specific Activity ◽  
High Specific Activity ◽  
High Yield ◽  
Liquid Media ◽  
Penicillic Acid ◽  
Stationary Culture ◽  
Radioactive Compound ◽  
Growth Substrates ◽  
Label Incorporation

14C-Labeled penicillic acid was produced by stationary culture incubation of Penicillium cyclopium (NRRL 1888) on a modified Raulin-Thom broth medium containing 14C-labeled acetate. Approximately 1.2 g of radioactive compound, with a specific activity of 23.0 μCi/mmole, was produced in 9 days in 1500 ml of the broth. Incorporation of the isotope into penicillic acid was 11. 9%. Production of the radiolabeled compound with high specific activity was achieved by correlating the monitoring of expired 14C-CO2 with production of penicillic acid during the fermentation. The effects of various growth substrates, pH, and incubation times on production of non-labeled penicillic acid also were investigated. Results show that sterile rice is an excellent substrate, that among liquid media examined, higher yields were obtained in stationary rather than in shake cultures, and that higher yields of penicillic acid were obtained at pH 3.5 or lower. Simultaneous monitoring of penicillic acid production and 14C-label incorporation is essential to detect and isolate a high yield of labeled compound with high specific activity.

scholarly journals High yield synthesis of high specific activity R-(−)-[11C]epinephrine for routine PET studies in humans

1993 ◽  
Vol 20 (8) ◽  
pp. 939-944 ◽  
Author(s):  
Pulak K. Chakraborty ◽  
David L. Gildersleeve ◽  
Douglas M. Jewett ◽  
Steve A. Toorongian ◽  
Michael R. Kilbourn ◽  
...  
Keyword(s):  
Specific Activity ◽  
High Specific Activity ◽  
High Yield

scholarly journals Both Subunits of ATP-Citrate Lyase from Chlorobium tepidum Contribute to Catalytic Activity

2006 ◽  
Vol 188 (18) ◽  
pp. 6544-6552 ◽  
Author(s):  
Wonduck Kim ◽  
F. Robert Tabita
Keyword(s):  
Catalytic Mechanism ◽  
Specific Activity ◽  
High Specific Activity ◽  
Small Subunit ◽  
High Yield ◽  
Chlorobium Tepidum ◽  
Atp Citrate Lyase ◽  
Citrate Lyase ◽  
Green Sulfur

ABSTRACT ATP-citrate lyase (ACL) is an essential enzyme of the reductive tricarboxylic acid (RTCA) pathway of CO2 assimilation. The RTCA pathway occurs in several groups of autotrophic prokaryotes, including the green sulfur bacteria. ACL catalyzes the coenzyme A (CoA)-dependent and MgATP-dependent cleavage of citrate into oxaloacetate and acetyl-CoA, representing a key step in the RTCA pathway. To characterize this enzyme from the green sulfur bacterium Chlorobium tepidum and determine the role of its two distinct polypeptide chains, recombinant holo-ACL as well as its two individual subunit polypeptides were synthesized in Escherichia coli. The recombinant holoenzyme, prepared from coexpressed large and small ACL genes, and the individual large and small subunit polypeptides, prepared from singly expressed genes, were all purified to homogeneity to high yield. Purified recombinant holo-ACL was isolated at high specific activity, and its k cat was comparable to that of previously prepared native C. tepidum ACL. Moreover, the purified recombinant large and small subunit polypeptides were able to reconstitute the holo-ACL in vitro, with activity levels approaching that of recombinant holo-ACL prepared from coexpressed genes. Stoichiometric amounts of each subunit protein were required to maximize the activity and form the most stable structure of reconstituted holo-ACL. These results suggested that this reconstitution system could be used to discern the catalytic role of specific amino acid residues on each subunit. Reconstitution and mutagenesis studies together indicated that residues of each subunit contributed to different aspects of the catalytic mechanism, suggesting that both subunit proteins contribute to the active site of C. tepidum ACL.

scholarly journals Synthesis and Initial In Vivo Evaluation of [11C]AZ683 – a Novel PET Radiotracer for Colony Stimulating Factor 1 Receptor (CSF1R)

2018 ◽  
Author(s):  
Sean S. Tanzey ◽  
Xia Shao ◽  
Jenelle Stauff ◽  
Janna Arteaga ◽  
Phillip Sherman ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Radiochemical Purity ◽  
Specific Activity ◽  
High Specific Activity ◽  
Colony Stimulating Factor ◽  
Positron Emission ◽  
New Strategy ◽  
Activity Yield ◽  
Stimulating Factor

Positron emission tomography (PET) imaging of Colony Stimulating Factor 1 Receptor (CSF1R) is a new strategy for quantifying both neuroinflammation and inflammation in the periphery since CSF1R is expressed on microglia. AZ683 has high affinity for CSF1R (Ki = 8 nM; IC50 = 6 nM) and >250-fold selectivity over 95 other kinases and, in this paper, we report the radiosynthesis of [11C]AZ683 and initial evaluation of its use in CSF1R PET. [11C]AZ683 was synthesized by 11C-methylation of the desmethyl precursor with [11C]MeOTf in 3.0% non-corrected activity yield (based upon [11C]MeOTf), >99% radiochemical purity and high specific activity. Preliminary PET imaging with [11C]AZ683 revealed no brain uptake in rodents and nonhuman primates suggesting that [11C]AZ683 is a poor candidate for imaging neuroinflammation, but that it could still be useful for peripheral imaging of inflammation.

scholarly journals Preparation of a whole cell catalyst overexpressing acetohydroxyacid synthase of Thermotoga maritima and its application in the syntheses of α-hydroxyketones

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yan-Fei Liang ◽  
Le-Tian Yan ◽  
Qiao Yue ◽  
Ji-Kui Zhao ◽  
Cai-Yun Luo ◽  
...  
Keyword(s):  
Good Yield ◽  
Specific Activity ◽  
Thermotoga Maritima ◽  
High Specific Activity ◽  
High Yield ◽  
Acetohydroxyacid Synthase ◽  
Whole Cell ◽  
High Yields ◽  
First Time ◽  
Excellent Stability

Abstract The large catalytic subunit of acetohydroxyacid synthase (AHAS, EC 2.2.1.6) of Thermotoga maritima (TmcAHAS) was prepared in this study. It possesses high specific activity and excellent stability. The protein and a whole cell catalyst overexpressing the protein were applied to the preparation of α-hydroxyketones including acetoin (AC), 3-hydroxy-2-pentanone (HP), and (R)-phenylacetylcarbinol (R-PAC). The results show that AC and HP could be produced in high yields (84% and 62%, respectively), while R-PAC could be synthesized in a high yield (about 78%) with an R/S ratio of 9:1. Therefore, TmcAHAS and the whole cell catalyst overexpressing the protein could be practically useful bio-catalysts in the preparation of α-hydroxyketones including AC, HP, and R-PAC. To the best of our knowledge, this is the first time that bacterial AHAS was used as a catalyst to prepare HP with a good yield, and also the first time that TmcAHAS was employed to synthesize AC and R-PAC.

scholarly journals Preparative isolation of the two forms of pig pancreatic pro-(carboxypeptidase A) and their monomeric carboxypeptidases A

1985 ◽  
Vol 229 (3) ◽  
pp. 605-609 ◽  
Author(s):  
M Vilanova ◽  
J Vendrell ◽  
M T López ◽  
C M Cuchillo ◽  
F X Avilés
Keyword(s):  
Amino Acid ◽  
Specific Activity ◽  
High Specific Activity ◽  
High Yield ◽  
Binary Complex ◽  
Acid Hydrolase ◽  
Carboxypeptidase A ◽  
Preparative Isolation

A method is reported for the preparative isolation of the two forms of pro-(carboxypeptidase A) from pig pancreas: the monomer and the binary complex with pro-(proteinase E). This method, which is mainly based on chromatography on DEAE-Sepharose at pH 5.7, allows these proenzymes to be prepared more quickly and in safer conditions than with other reported methods. Undegraded and homogeneous carboxypeptidase A1 and A2 species (peptidyl-L-amino acid hydrolase, EC 3.4.17.1), in monomeric forms with high specific activity, are also obtained in high yield by controlled trypsin activation of either of the pro-(carboxypeptidases A) followed by chromatography on DEAE-Sepharose at pH 5.8 under dissociating conditions (7 M-urea).

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