Potassium Ferricyanide

And so, potassium ferricyanide was added in aliquots resulting in the various equilibrium absorption spectra shown in Fig. 1.

From: Microsomes and Drug Oxidations , 1977

Branched-Chain Amino Acids, Office B

Kirill M. Popov , ... Robert A. Harris , in Methods in Enzymology, 2000

Reagents

Potassium ferricyanide, 100  mM (prepare fresh daily)

Buffer E: 30   mM potassium phosphate, 0.1   yardThou EDTA (pH   7.5 at 4º); 2   × buffer E is prepared as a stock solution

DEAE-Sephacel CL-4B (Pharmacia LKB Biotechnology)

Protein A-Sepharose CL-4B (Pharmacia LKB Biotechnology)/

Anti-BCKDH complex antibody-bound protein A-Sepharose: The E1 component of rat liver BCKDH complex prepared according to the method of Melt and Yeaman 15 is used to fix antibody against the BCKDH complex. vii The antiserum prepared with the E1 preparation contains both anti-E1 and anti-E2 antibodies, because the E1 preparation is contaminated with a trace of E2 and E2 is very antigenic; however, the antiserum is devoid of antibodies against BCKDH kinase. Anti-BCKDH complex antibiotic-jump poly peptide A-Sepharose is prepared past mixing, at room temperature for twenty   min, 2   ml of the antiserum with 0.8   ml of protein A-Sepharose gel equilibrated with buffer D containing 0.1% (w/v) Tween xx and 0.15 M KCl and and so washing with the same buffer

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l-(+)-Lactate

Hans-Jürgen Hohorst , ... Hans-Dieter Söling , in Methods of Enzymatic Analysis, 1965

Reagents

ane

Potassium ferricyanide, Yard 3[Fe(CN)half dozen], A. R.

2

Sodium pyrophosphate, Na4P207-10 H20, A. R.

3

Hydrochloric acid, A.R., 2N

4

Lactic acid (racemate)ane Thou aqueous solution or Na or Li salt

v

Lactic dehydrogenase, LDHfrom yeast (purified at to the lowest degree 20 to 25-fold). For the preparation of the enzyme according to 4) , see the Appendix, p. 274.

6

Perchloric acid, A. R.; sp. gr. 1.67; ca. 70% (w/w)

seven

Potassium hydroxide, A. R., IN

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Vitamin

Buddhi Prakash Jain , ... Shweta Pandey , in Protocols in Biochemistry and Clinical Biochemistry, 2021

Definition

Vitamin B1 is a h2o-soluble vitamin. Thiamine pyrophosphate (TPP) is the active grade of vitamin B1. Vitamin B1 acts as a cofactor of many enzymes. Thiamine is involved in nerve conduction, muscular functioning, metabolism, etc. The deficiency of thiamine causes beriberi disease, appetite loss, and neuritis.

Rationale

Thiamine is oxidized to a fluorescent compound, thiochrome past element of group i potassium ferricyanide. The fluorescence of the thiochrome is measured by fluorimeter. The normal serum vitamin B1 varies betwixt 2.5 and vii.five  μg per 100   mL.

Materials, equipment, and reagents

A.

Reagents : Potassium chloride, sodium hydroxide, potassium ferricyanide, standard thiamine solution, conc. HCl, isobutyl booze, sodium sulfate, sample.

B.

Glassware: Chalice, measuring cylinder, test tube.

C.

Instrument: Fluorometer.

Protocols

1.

Accept 5   mL of thiamine standards (0.ane–1   μg/mL) in dissimilar test tubes.

2.

Add 3   mL of NaOH (15%) in each of the test tubes.

three.

Add 100 μL potassium ferricyanide and mix well for the oxidation process.

4.

Add 15   mL of isobutanol. Mix well for ane   min allowing the tubes to stand till two layers separate.

5.

Remove the aqueous layer advisedly.

six.

The isobutanol layer contains thiochrome. To this add 2–three   g of sodium sulfate and mix well. Information technology will absorb the water and the solution becomes articulate.

7.

Measure the fluorescence of the articulate solution using a fluorometer.

eight.

Set up sample blank past using five   mL of 25% KCl and repeat all the steps except the addition of potassium ferricyanide. Set up cipher of fluorometer using this blank solution.

9.

Accept 5   mL of the test sample and repeat all the steps and measure fluorescence.

Calculation

From the fluorescence of the concentration of the standard solution of the vitamin B1 in an unknown sample can exist calculated.

Precursor techniques

1.

Sodium hydroxide (15%): Dissolve 15   g NaOH in 100 water.

2.

Potassium ferricyanide (1%): Dissolve i  grand of potassium ferricyanide in 100   mL of h2o.

3.

Potassium chloride (25%): Dissolve 250   grand of potassium chloride in 1   50 of 0.1   Northward HCl.

4.

Standard thiamine solution:

(A)

Stock: Dissolve 10   μg of thiamine in 10   mL of 25% KCl (one   μg/mL).

(B)

Working: Serial dilution of stock solution in 25% KCl (0.ane–1   μg/mL).

Prophylactic considerations and standards

i. Handle the HCl advisedly. HCl is highly toxic. Dilute it by adding acid in h2o.

2. Solutions should be freshly prepared.

Assay and statistics

The given serum sample contains vitamin B1_______ μg/100   mL.

Alternative methods/procedures

Determination of vitamin B1 by the spectrophotometric method.

Summary

This is the fluorometric method. Vitamin B1 is oxidized by potassium ferricyanide into a fluorophore thiochrome whose fluorescence is the directly measurement of the thiamine or vitamin B1 in the sample.

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Ring Systems with at to the lowest degree Two Fused Heterocyclic Five- or Vi-membered Rings with no Bridgehead Heteroatom

A.J. Moore , in Comprehensive Heterocyclic Chemistry Three, 2008

10.02.7.1.2 [five+0] Electrophilic cyclizations

The cyclization of two- and 3-(thioacetamido)thiophene mediated by potassium ferricyanide was first reported past Zhirayakov and Levkoev <1958DOK(120)1035, 1996CHEC-II(7)49>. This methodology has now been extended to include the preparation of ii-carbamoylthieno[2,3-d]thiazoles 68 and 2-carbamoylthieno[3,2-d]thiazoles 70 past potassium ferricyanide-mediated cyclizations of monothiooxamides 67 ( Scheme 14 ) <2004RJO137, 2004ZOK146> and 69 ( Scheme 15 ) <2003RJO1161, 2003ZOK1232>, respectively.

Scheme xiv.

Scheme 15.

Another electrophilic cyclization strategy is reported in which acid-mediated cyclization of benzofuro-ii-hydrazones 71 afforded benzofuro[3,2-c]pyrazoles 72 (Equation 12) <2004FA849>. The benzofuro[iii,2-c]pyrazoles 72 were investigated for their binding at both fundamental and peripheral benzodiazepine receptors. An coordinating cyclization of thienyl-2-hydrazones to thieno[2,3-c]pyrazoles with polyphosphoric acid has also been reported <1996CHEC-Ii(7)49>. A thermal cyclization, in the absence of an acid catalyst, of pyrrolo-2-hydrazone 73 is reported to afford a pyrrolo[3,2-c]pyrazole 74 (Equation 13) <2006TL433>. A one-aryl-3-(ii-thienyl)[ane,2,3]triazolo[1,5-b]isoquinolinium salt 75 underwent an interesting electrophilic thermal rearrangement in trifluoroacetic acid (TFA), via a ring-opened nitrenium cation 76 that reacted exclusively to afford thieno[3,2-c]pyrazole 77 ( Scheme 16 ) <1999JOC5499>. In contrast, repeating the experiment in the absence of TFA gave a mixture of ii products 77 and 78 . The absence of 78 in the former reaction is suggested to arise from deactivation of the isoquinoline moiety to electrophilic substitution through protonation.

(12)

(13)

Scheme 16.

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Histochemical Detection of Enzymes

Franz Duspiva , in Methods of Enzymatic Analysis, 1965

Reagents

1.

Tris-hydroxymethyl-aminomethane, tris

ii.

Sodium chloride

iii.

Potassium ferricyanide, M four[Iron(CN)6] · 3 HiiO

4.

Potassium ferrocyanide, [Grand3Fe(CN)six]

5.

v-Bromo-4-chloro-indoxyl acetate *)

6.

Ethanol, 30% (w/w)

7.

Acetic acrid, glacial

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Polycondensation

R. Guo , J.E. McGrath , in Polymer Science: A Comprehensive Reference, 2012

5.17.2.1.4(iii)(a) Anion-radical polymerization

In the presence of catalytic amounts of an oxidative initiator, such as atomic number 82 oxide, potassium ferricyanide, or fifty-fifty air, the synthesis of PAEs from bromophenols proceeds via a anion-radical intermediate (Due south RNi′ machinery). 73–75 In this case, the polymer chain is extended via the addition of a phenoxy radical to a phenolate anion. More than recently, the utilization of the phase transfer catalysis (PTC) organisation has been shown to lead to well-defined PPOs with controllable molecular weights and functionality. 76 Past using diverse finish-blocking phenols, such equally 2,4,six-trimethylphenol 77 or isphenol A-type phenols 78 as a concatenation-initiating phenol, functional PPO oligomers accept been obtained with well-controlled molecular weights, with either single phenolic terminate groups that can exist further functionalized or two phenolic chain ends.

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Petroselinum crispum: a Review

C. Agyare , ... J.A. Apenteng , in Medicinal Spices and Vegetables from Africa, 2017

6.2 Antioxidant activity

Using the 2,two,i-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and potassium ferricyanide–ferric chloride analysis, Marín et al. (2016) reported that essential oils extracted from parsley flowers by hydrodistillation exhibited antioxidant activity at 500, chiliad, 2000, and 5000 mg/mL with the highest concentration exhibiting inhibition of DPPH radical at 64.28% and ferric reducing power of 0.93 mmol/L Trolox. Haidari et al. (2011) by ways of the ferric reducing ability of plasma (FRAP), lipid peroxidation, and spectrophotometry [HPLC and bicinchoninic acrid kit] assay reported that aqueous extracts of P. crispum leaves and its isolated flavonoids (quercetin and kaempferol) at a concentration of 5 mg/g significantly (p < 0.001) increased the total antioxidant capacity and decreased malondialdehyde concentration in hyperuricemic rats.

Leaf and stem aqueous and methanol extracts of P. crispum have been identified to possess antioxidant activity in vitro via the DPPH radical-scavenging, ion-chelating, and hydroxyl radical assays (Wong and Kitts, 2006). Methanol-derived leafage extracts exhibited significantly (p < 0.05) greater radical-scavenging action toward both lipid- and water-soluble radicals, which was attributed to the total phenolic content. Ferrous ion-chelating activity was significantly (p < 0.05) greater in the stalk methanol extracts.

Sęczyk et al. (2015) using the Folin–Ciocalteu assay reported that wheat pasta fortified with powdered P. crispum leaves [ane–4% (due west/due west)] exhibited antioxidant activity in vitro. Essential oil from seeds of P. crispum exhibited antioxidant activity using β-carotene bleaching, DPPH gratis radical scavenging and Fe2+ metal–chelating assays. The EC50 values of the β-carotene bleaching assay and DPPH free radical scavenging analysis of the crude P. crispum oil dissolved in methanol were 5.12 and 80.21 mg/mL, respectively (Zhang et al., 2006) (Tabular array 25.1).

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New Approaches for Flavin Catalysis

Stephen A. Marshall , ... David Leys , in Methods in Enzymology, 2019

4.4 Notes

It is crucial that any oxidant used is made fresh and kept under strict anaerobic conditions immediately prior to utilize. Potassium ferricyanide is an orange solid that can be flushed with nitrogen before beingness dissolved in anaerobic buffer in the anoxic chamber. We recommend making a concentrated stock solution and performing series dilutions downwards to a working concentration to ensure it is fully anaerobic. Hydrogen peroxide can be purchased as a 30% or roughly 10  K stock solution but it is unstable and slowly decomposes in calorie-free. Stock solutions can be sparged with oxygen free nitrogen before being taken into the anaerobic chamber and then diluted down to a working concentration with anaerobic buffer earlier use.

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Five-membered Rings with Two Heteroatoms, each with their Fused Carbocyclic Derivatives

B. Chen , West. Heal , in Comprehensive Heterocyclic Chemistry III, 2008

iv.06.ix.6.1 Jacobson synthesis

The Jacobson synthesis of benzothiazoles 235 involves oxidative cyclization of an arylthioamide 236 on an unsubstituted ortho -position, using potassium ferricyanide in a bones medium ( Scheme 94 ) <1999J(P1)1437>. This method has been applied to the synthesis of various benzothiazoles, including analogues of kuanoniamine A <2004OBC3039>.

Scheme 94.

Recently, the synthesis of 2-substituted benzothiazoles has been reported via an intramolecular cyclization of arylthioamides 237 by using hypervalent iodine reagents (typically Dess–Martin periodinane, DMP) in CH2Cl2 at ambience temperature. The reaction proceeds via a thiyl radical 238 in high yields (85–95%) to give benzothiazoles 239 and is as well amenable to solid-phase synthesis ( Scheme 95 ) <2006JOC8261>.

Scheme 95.

It has been postulated that this radical cyclization and the Jacobson reaction mechanism mentioned above may be linked. Nether the Jacobson conditions, the cyclization would appear to depend on the electron density of the effluvious band, and on the stability of the ions 240a and 240b ( Scheme 96 ). Where R or R1 are H or OMe the reaction proceeds via cation 240b with the replacement of the ortho-hydrogen, in proficient yields. Where R is more electron withdrawing, the reaction slows downwardly (R   =   H to Br to NOii, leads to 80%, 45% and 0% yields, respectively, after 24   h) indeed, and where R   =   NO2 and R1  =   OMe the reaction gave only 24% yield after vii days. Only small-scale amounts of 240c or 240b are formed where the negative charge can be delocalized onto the R-groups, leading to predominance of 240a , which in plough means that greater electron density is required on the ring for cyclization to occur. Conversely, when R is electron-donating, replacement of the ortho hydrogen does not occur. The presence of electron-altruistic groups para to the thioamide stabilizes cation 240b , rendering it unreactive. The radical species 240c , an intermediate between 240 and 240b , may then be the reacting species and the ortho-OMe is substituted in low yield <2004OBC3039>. Detailed studies of these mechanistic pathways are ongoing.

Scheme 96.

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The complete blood count and white claret cell differential

Alisha D. Ware , in Contemporary Practice in Clinical Chemical science (Fourth Edition), 2020

Hemoglobin

Hemoglobin is measured spectrophotometrically following conversion of the molecule to cyanomethemoglobin [ane,5,16] . Post-obit RBC lysis, potassium ferricyanide oxidizes the ferrous ion of hemoglobin to the ferric ion of methemoglobin. Methemoglobin is so converted to cyanomethemoglobin following the add-on of potassium cyanide. Absorbance at 540  nm is measured, and the intensity of this signal corresponds to hemoglobin concentration [5]. Hemoglobin is reported in grams per deciliter (yard/dL). A normal hemoglobin measurement is 14–17.5   g/dL for developed males and 12–15   grand/dL for adult females [3].

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