Isokok

“Peroxisomes are so named because they usually contain enzymes that use oxygen to remove hydrogen atoms from specific substrates in an oxidative reaction that produces hydrogen peroxide (H2O2) (McCance & Huether, pg. 7).

oxidation in the mitochondria within each cell. Carbohydrates, proteins, and fats can all be metabolized as

One of the best-studied peroxidases is horseradish peroxidase (HRP), which has a heme-iron co-factor. In most heme-peroxidases the iron atom in the active center undergoes a reversible change of its oxidation state. The reaction proceeds in three distinct steps. In first step, the resting state high-spin Fe(III) is present, which is oxidized by hydrogen peroxide to form an unstable intermediate called compound I (Co-I) with Fe(IV), releasing water in the process. Compound I is not a classical enzyme–substrate complex, but rather a reactive intermediate with a higher formal oxidation state (­5 compared with ­3 for the resting enzyme). Thus, compound I is capable of oxidizing a range of reducing substrates. This reactive intermediate oxidizes

J. Moldovan & B. Nilson, (2010), Lab 4 – Enzyme Kinetics, UBCO BIOL/BIOC 393, UBC Vista accessed Monday, November 8th, 2010.

Sissela Bok opens a controversial topic on violence as entertainment which explores the effect of the increasing of violence both in fiction and in real life. Not only do films, television shows, and video games evidence an escalating level of graphic violence, but daily news of war and other human brutality are as bad as well. As less time pass on doing physical activities and an increase in using electronic devices as increases, particularly by teens, there is growing concern about a possible link between violence viewing content and actual behavior. Bok draws a balanced image, naming some possible benefits from violence. One of the benefits could be the redirection of human physical and verbal aggression and the confrontation of fears in

For example, although the unesterified form of AA is in nM range in blood (Brash 2001), in the other tissues the unesterified AA concentration has been reported to be remarkably higher, for example ~13-44 µM in umbilical cord and intervillous space (Benassayag, Mignot et al. 1997), ~19 µg/g (approximately equivalent to 60 µM) in skin (Hammarstrom, Hamberg et al. 1975), and ~75 µg/g (approximately equivalent to 250 µM) in liver (Edpuganti and Mehvar 2013). Therefore, in several published studies investigating P450-mediated AA metabolism in vitro, 50-100 µM of AA was deemed to be mimicking the in vivo situation (Xu, Falck et al. 2004, Imaoka, Hashizume et al. 2005). Noteworthy, in response to stimuli, the release of the free AA has been reported to be remarkably increased (Buczynski, Dumlao et al. 2009). The unesterified AA is then metabolized into several biologically active metabolites, termed eicosanoids, by one of three groups of enzymes: cyclooxygenases, lipoxygenases, or microsomal P450 enzymes (Buczynski, Dumlao et al.

Enzymes are seen as the “tools” of nature. A fundamental task of proteins is to act as enzymes—catalysts that increase the rate of chemical reactions within cells. Enzymes quicken the rates of reactions by well over a million-fold, so reactions that would usually take years can be done in seconds in the presence of a catalysts. In this experiment the effects on catechol oxidase activity is being tested. Proteins can be denatured by salt concentration being too high. The purpose of our experiment was to determine if the addition of NaCl (salt) solution would have any effect to the rate of reaction of the enzyme. The null hypothesis was that NaCl would have no effect on the rate of reaction of the enzyme. Our hypothesis was that NaCl would speed up of the rate of reaction, due to the

Urate hydroperoxide is formed when urate is oxidized to a radical that subsequently adds to superoxide. It is produced by activated white blood cells called neutrophils and by enzymes that include xanthine oxidase and peroxidase. Previous studies characterized the formation of urate hydroperoxide and its oxidation of small biomolecules (1-3). My work involved optimizing urate hydroperoxide production by xanthine oxidase and lactoperoxidase, and exploring how it reacts with thiols and thiol-dependent enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH).

There is still controversy between magnetic nuclear resonance data and experimentally demonstrated data on chemical property of polyenes towards binding of ergosterol [M. Baginski et.al, 1997] [J. Milhaud et.al. 2002]. Some research suggested that polyene drugs are able to induce an oxidative stress (particularly in C. albicans [M. A. Ghannoum, 1999] [R. A. Akins, 2005] as well as their activity seems to be reduced in hypoxic conditions [P. A. Warn et al. 2004].

Jones, A. E. & H., G., 1963. Oxidation of succinate and the control of the citric acid cycle in the mitochondria of guinea-pig liver, mammary gland and kidney. Biochemical Journal, 87(3), p. 639–648.

Lactose was the substrate while O-nitrophenol was the product. The appearance of color after a particular duration of time made it easier to determine the progress of the reaction. It was hypothesized that low and high-temperature decrease enzyme activity. Moreover, it was anticipated that addition of lactose would increase enzyme activity up to a certain point, followed by a decrease in enzyme activity.

With all living organisms, a process known as cell respiration is integral in order to provide the body with an essential form of energy, adenosine triphosphate (ATP). Oxygen, although an essential part of this process, can form reactants from colliding with electrons associated with carrier molecules. (pb101.rcsb.org, 2017). Hydrogen peroxide is an integral product of this reaction but is known to impose negative effects on the body if high levels are introduced. Explicitly, this reaction is caused “If oxygen runs into (one of these) carrier molecules, the electron may be accidentally transferred to it. This converts oxygen into dangerous compounds such as superoxide radicals and hydrogen peroxide, which can attack the delicate sulphur atoms and metal ions in proteins.” (pdbh101.rcb.org, 2017). Research has suggested that the hydrogen peroxide can be converted into hydroxyl radicals, known to mutate DNA, which can potentially cause bodily harm due to DNA’s role in the synthesis of proteins. These radicals can cause detrimental effects on the human body, and studies have suggested a link to ageing. Due to the harmful effects of these H2o2, it is important that the body finds a way to dispose of hydrogen peroxide before concentrations are too great.

Protein purification is a process that can be employed to separate a single protein from a larger starting material which may be anything from an organ to a cell. Isolating a purified protein from a larger fraction enables further analysis such as determination of amino acid sequence, potential biological function, and even evolutionary relationship. (Cuatrecasas 1970) In this experiment, the enzyme lactate dehydrogenase will be purified, this enzyme is found extensively in human cells and catalyzes the conversion of lactate to pyruvate, an essential part in energy production. LDH is a key part of anaerobic energy production especially within glycolysis in which LDH catalyzes the conversion of the reverse reaction, pyruvate to lactate, generating NAD+ from NADH, reproducing the oxidized form of the coenzyme which can be used for oxidative respiration. (Markert 1963) Due to the fact that number of purification steps correlates with the purity of the protein multiple purification techniques will be used to isolate a pure form of LDH. LDH will be isolated from a larger “cytosol” fraction collected from a homogenized rat liver in a previous fractionation exercise. Of the procedures that will be used to isolate and purify proteins from a larger fractionate are a set of techniques collectively known as chromatography. These techniques all have the same premise, in that they consist of a stationary phase, also known as the

To fully understand the biological role of isoketals in oxidative injury and counter their detrimental effects, efforts to identify selective scavengers of isoketals were undertaken. A lead compound, pyridoxamine (PM) was first discovered as a carbonyl scavenger in 1996 by Billy G. Hudson and colleages (Booth, Khalifah et al. 1996), and identified through initial screens, where Amarnath and colleagues determined second-order reaction rates for a series of primary amines relative to N-α-acetyl-lysine (Amarnath, Amarnath et al. 2004). Pyridoxamine is a vitamer in the vitamin B6 family, and through our studies, PM was found to effectively intercept isoketals from adducting to cellular amines. Through the initial screen, pyridoxamine was found

Chemicals were purchased from Aldrich chem. Co. England. Fresh human serum (obtained from Medical Research Institute Blood Bank) was used as source of the enzymes. The enzymes SALT and SAST activities were assayed by the method of Reitman and Frankel.(13) In this method; the keto acid formed were measured colourimetricaly after combination with 2,4-dinitrophenyl hydrazine, then the hydrazone formed was measured at 530