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.

Fragment D Immunoreacivity: The Influence of Iodination and Calcium Environment

1979 ◽  
Author(s):  
B. Kudryk ◽  
M. Blombäck
Keyword(s):  
Conformational Changes ◽  
Binding Sites ◽  
Specific Activity ◽  
High Specific Activity ◽  
Antigenic Determinants ◽  
Affinity Binding ◽  
Compact Structure ◽  
High Affinity Binding ◽  
High Affinity ◽  
Chloramine T

Human fragment D (Fg-Ds) has heen iodinated using both the Chloramine-T and lactoperoildaae methods. The specific activity was similar regardless of the method used. However, binding to a specific antibody was different for each preparation. The antigen labeled by the Chloramine-T method bound to a maximum of 40% the other labeled product bound up to 85%. A correlation between the decree of immunoreactivity and avidity for a fihrinmcnomer conjugate vas found also. Fibrinmonomer bound about twice the ajnount of lactoperoxidase iodinated Fg-Da ae it did the Chloramine-T product. The use of these conjugates in the purification of immunoreactive Fg-Ds of high specific activity will be discussed. High affinity binding sites for calcium have recently been demonstrated in fibrinogen. Tha presence of bound calcium is also believed to protect Fg-Ds f m further digestion by plasmin. This is probably due to the formation of a more compact structure. However, conformational changes for calcium bound fibrinogen or Fg-Ds have not been observed. We tested the immunoreactivity of the lactoperoxidase iodinated Fg-Ds in presence and absence of calcium. Differences were found and this data suggests that soma modification of antigenic determinants takes place as a consequence of calcium in the environment.

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

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 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.

THE DEVELOPMENT OF A RADIOIMMUNOASSAY FOR ARGININE-VASOPRESSIN: PRODUCTION OF ANTISERA AND LABELLED HORMONE; SEPARATION TECHNIQUES; SPECIFICITY AND SENSITIVITY OF THE ASSAY IN AQUEOUS SOLUTION

1972 ◽  
Vol 52 (2) ◽  
pp. 279-288 ◽  
Author(s):  
C. R. W. EDWARDS ◽  
T. CHARD ◽  
MURIEL J. KITAU ◽  
MARY L. FORSLING ◽  
J. LANDON
Keyword(s):  
Arginine Vasopressin ◽  
Specific Activity ◽  
Limit Of Detection ◽  
High Specific Activity ◽  
Ion Exchange Resin ◽  
Cross Reactivity ◽  
Amino Acid Sequences ◽  
Simple Method ◽  
Specificity And Sensitivity ◽  
Chloramine T

SUMMARY A radioimmunoassay for vasopressin was developed using antibodies produced against conjugated and non-conjugated arginine vasopressin. Despite the fact that the vasopressin molecule has only eight amino acids, cross reactivity studies showed that these antibodies were specific for different amino acid sequences. Labelled hormone of high specific activity (350–800 μCi/μg) was produced by a modification of the chloramine-T method. Unreacted iodide was removed by the batchwise addition of an ion-exchange resin. Other techniques of purification produced no advantage over this simple method. Several methods of separating antibody-bound and free hormone were studied. All except chromatoelectrophoresis proved satisfactory. Ammonium sulphate or ethanol precipitation of bound hormone was chosen because of simplicity, speed and reproducibility. The lower limit of detection of the assay was 80 pg arginine vasopressin/ml diluent buffer. Therefore an extraction and concentration procedure is necessary for the measurement of basal circulating levels of the hormone.

Fragment D Immunoreactivity: The Influence of Iodination and Calcium Environment

1979 ◽  
Author(s):  
B. Kudryfc ◽  
N. Blombäck
Keyword(s):  
Conformational Changes ◽  
Specific Antibody ◽  
Binding Sites ◽  
Specific Activity ◽  
High Specific Activity ◽  
The Other ◽  
Antigenic Determinants ◽  
Affinity Binding ◽  
Compact Structure ◽  
Chloramine T

Human fragment D (Fg-Ds) has been iodinated using both the Chloramine-T and lactoperoxidase methods. The specific activity was similar regardless of the method used. However, binding to a specific antibody was different for each preparation. The antigen labeled by the Chloramine-T method bound to a maximum of 40%, the other labeled product bound up to 85%. A correlation between the degree of immunoreactivity and avidity for a fibrinmonomer conjugate was found also. Fibrinmonomer bound about twice the amount of lactoperoxidase iodinated Fg-Ds as it did the Chloramine-T product. The use of these conjugates in the purification of immunoreactive Fg-Ds of high specific activity will be discussed. affinity binding sites for calcium have recently been demonstrated in fibrinogen. The presence of bound calcium is also believed to protect Fg-Ds from further digestion by plasmin. This is probably due to the formation of a more compact structure. However, conformational changes for calcium bound fibrinogen or Fg-Ds have not been observed. We tested the immunoreactivity of the lactoperoxidase iodinated Fg-Ds in presence and absence of calcium. Differences were found and this data suggests that some modification of antigenic determinants takes place as a consequence of calcium in the environment.

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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