Explain Why Methionine Residues Are More Important Than Cysteine

Methionine has a thioether side chain, and cysteine's contains a thiol group. These side chains exist as free thiols inside the cell, and are oxidised causing them to pair up and form disulphide bonds in an extracellular environment.

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.

Peroxidase is an enzyme that breaks down hydrogen peroxide in our cells (Bansal et. al., 2016). Peroxidase is essential in life because hydrogen peroxide can cause damage to the cell. Hydrogen peroxide is the substrate to the peroxidase enzyme, where it binds to the active site and is broken down into water. In order to monitor the breakdown of hydrogen peroxide, the colorless dye guaiacol binds to the peroxidase and becomes oxidized as hydrogen peroxide is reduced to water, which then turns brown. Hydroxylamine is an inhibitor that has a similar structure to hydrogen peroxide. When hydroxylamine binds to the active site of peroxidase, it inhibits hydrogen peroxide from binding, thus preventing the breakdown of hydrogen peroxide (Lab Handout,

Main compounds of the enzymatic antioxidant system are three, namely, SOD, CAT and tT which have an important role in detoxifying of H2O2 and superoxide anion in cells. Ample of hepatotoxic drugs induces the liver damage by lipid peroxidation indirectly or directly. The proxy radicals are main factors that mediate lipid peroxidation leading to liver injury and kidney damage(41). MDA as a main reactive aldehyde appears during polyunsaturated fatty acid peroxidation in the biological

One of the reasons your suffering, is your deficiency in the anti-viral amino acid Lysine. Glutamine supports your intestines and nervous system. Methionine helps the liver and detoxification systems. Glycine prevent cancer, metabolic disorder and helps liver protection. Valine is a branched-chain amino acid (BCAA) that works with the other two BCAAs, isoleucine and leucine, to promote normal growth, repair tissues, regulate blood sugar, and provide the body with energy. Valine helps stimulate the central nervous system, and is needed for proper mental functioning. Valine helps prevent the breakdown of muscle by supplying the muscles with extra glucose for energy production during intense physical activity. Valine also helps remove potentially

Methionine has a thioether side chain, and cysteine's contains a thiol group. These side chains exist as free thiols inside the cell, and are oxidised causing them to pair up and form disulphide bonds in an extracellular environment.

Glutathione manages to act as a scavenger, neutralizing free radicals as they peruse the body. This counterbalance leads to the protection of our individual cells and thus our skin, eyes (lens, cornea, and retina), brain, heart, liver, kidneys, lungs, intestines as well as other tissues and organs from oxidative damages to ensure a better functioning,

Selenium is an essential trace element found in the body that works in conjunction with other vitamins to support the powerful detoxification process. When combined with Vitamin E, Selenium can help prevent oxidative stress from occurring in the body which is crucial in the prevention of many diseases such as heart disease and cancer. According to Dr. Mandal (2015), "Oxidative stress is essentially an imbalance between the production of free radicals and the ability of the body to counteract or detoxify their harmful effects through neutralization by antioxidants." Selenium goes to work in the body as a powerful antioxidant, and it is required for the production of Glutathione, which is a key antioxidant in our bodies. Antioxidants are important in keeping the body healthy by fighting off the free radicals that our cells are exposed to on a daily basis.

Your body is in a constant battle against infection, diseases and the formation of free radicals. However, there's a secret weapon that can help you fight against these things: antioxidants! Antioxidants are elements such as vitamins A, C and E that counteract the damage caused by free radicals and help protect your healthy cells. Free radicals are the molecules that contain unpaired electrons, which make them highly reactive. In this form, they can cause damage by attacking healthy cells, and when these cells grow weakened, you become more vulnerable to disease.

When we eat meat we just eat it without considering the harm it could cause. One of which is the products of meat metabolism within the cells such as the homocysteine in the methionine (homocysteine) cycle. The elevation of this substance in the body could cause cardiovascular diseases (CVD). Furthermore, Homocysteine is a non-protein amino acid which is a product of methionine metabolism (1). It can't be obtained from a diet, but it synthesized from methionine, which is a product of meat metabolism (1). Also, homocysteine depends on the presence of vitamin B6, B12, and folate to convert back into methionine or into cysteine (2). The critical problem is in the absence of one of these vitamins, so homocysteine won't be able to convert into either

oxidant production by pulmonary phagocytes overwhelms the antioxidant defenses and leads to lipid peroxidation, protein nitrosation, cell injury and lung scarring “(Khan, 2015).

Many animal studies have shown that lead is capable of causing oxidative stress in many organs (Patra et al., 2001). Toxicity of lead is mainly attributed to the induction of oxidative stress by disruption of the pro-oxidant/anti-oxidant balance, elevation of reactive oxygen and nitrogen species (ROS and RNS, respectively) such as superoxide radicals, hydrogen peroxide, hydroxyl radicals and lipid peroxides, and nitric oxide (Kumar and Reddy, 2012). Currently, N-acetyl-L-cysteine (NAC), derives from L-Cysteine and the precursor of glutathione (GSH), is a well-established cyto-protective drug against drugs induced hepatotoxicity and nephrotoxicity (Whyte et al., 2007; Akbulut et al., 2014), where it exerts antioxidant properties. L-Cysteine was utilized as a chelator of heavy metal to conserve against oxidative stress and inhibit damage to cells and tissues. L-cysteine, a sulfur-containing amino acid, is a nutritionally occurring non-essential amino

These include SOD (superoxide dismutase) and glutathione. At the same time, Nrf2 starts the detoxification of heavy metal and renews the CoQ10. As you might know, CoQ10 is a powerful antioxidant.

Confirming proteins in the ETC serves multiple functions opens up lots of possibility in the field of biochemistry and cell biology, enabling scientist to re-evaluate the presence of non-signaling protein and protein-lipid complex. Like mentioned earlier, ROS are the inevitable byproduct that is given off majorly by complex III (bc1) even under normal physiological conditions. Cytochrome c-CL complex demonstrates peroxidase activity and contributes to deplete ROS, reducing radical damage and signaling stress in cells. It thus wouldn’t be a surprise to observe proteins that are adjacent to bc1 to possess similar anti-oxidative function. Many studies have shown that elevation in cellular H2O2 concentration activates signaling pathways in hypoxia, mitochondrial ROS is considered as an integral part of cellular signal transduction in various processes.

The high MDA level mentioned in Cd-group our investigation was associated with a marked depletion of renal GSH by Cd exposure due to the direct binding of Cd to enzyme active sites, if it contains –SHgroups77. Significant decrease in the levels of these non-enzymatic antioxidants in Cd toxicity could lead to increased susceptibility of the renal tissue to free radical damage .GSH is a non-enzymatic antioxidant which acts as a first line of defense against oxidative stress78. The significant reduction in GSH levels that was recorded can be attributed to the increased use of GSH (by the renal tissues) to mop up excessive ROS that were generated during the process of Cd-induced renal injury 60. The depletion of GSH also seems to be a prime