User:Mkchem101/sandbox

Article evaluation
Article - Placebo studies


 * 1) Is everything in the article relevant to the article topic? Is there anything that distracted you?

Everything in the article relates to the topic. Article did not distract me because there is such limited information on this page.

2. Is any information out of date? Is anything missing that could be added? What else could be improved?

Information is not out of date, however, more information needs to be added. Such as, history/origin, and more studies were the placebo effect took place.

Adding more information and some pictures can improve this article.

3. Tone

Article tone is neutral and unbiased. Most viewpoints are represented, this can improve by adding more information such as more studies.

4. Sources

There are sources backing this article and the citations work. Sources came from well known and neutral sources such as The American Journal of Medicine, The Journal of Laboratory and Clinical Medicine, and Contemporary Clinical Trials, etc.

Week 3 task - Info for Chromium(III) acetate (CRAC) tris(aquo)hexa-μ2-acetato-μ3-oxo-trichromium(III) chloride hexahydrate
Properties of Chromium (III) Acetate


 * Molecular formula: C6H9CrO6
 * Molar mass: 229.128 g/mol
 * Melting point: >400° C
 * Boiling point: 212° F
 * Solubility in water: 675 g/L at 20° C
 * Solubility in water: 675 g/L at 20° C
 * Solubility in water: 675 g/L at 20° C

Chromium (III) Acetate

References


 * 1) The behavior of chromium acetate in qualitative analysis Charles B. DeWitt and George Baldwin 1937 14 (11), 541  10.1021/ed014p541
 * 2) Mechanism Study of the Cross-Linking Reaction of Hydrolyzed Polyacrylamide/Ac3Cr in Formation Water Lei Zhang, Chunsheng Pu, Haibo Sang, and Qing Zhao 2015 29 (8), 4701-4710 10.1021/acs.energyfuels.5b00149
 * 3) III. Two-Component Gel Catalysts Containing Chromium Oxide for the Aromatization of n-Heptane 10.1021/ja01850a072

External Links

https://pubchem.ncbi.nlm.nih.gov/compound/14012

Assignment topic
The topic I've chosen for the assignment is on Metallothionein, the wiki page has a decent amount of information. I wanted to elaborate more on


 * Primary function
 * Where MTs are located

Metallothionein - first 250 word contribution
Function

Metallothionein contain a rich thiol content, this causes metallothionein to bind a number of trace metals. Metallothionein binds several Zn ions. One of few eukaryotic proteins distinguished as having a role in substantial metal detoxification. Zinc and Cadmium are tetrahedrally coordinated to cysteine residues, each metallothionein protein molecule may bind up to 7 atoms of Zn or Cd. The biosynthesis of metallotionein appeared to have increased by several-fold throughout oxidative stress to shield the cells against cytotoxicity and DNA damage. Metallothionein are able to protect from oxidative stress. Some organisms that get induced with metallothionein could endure oxidation stress better. Metallothionein biosynthesis can also be induced by certain agents or conditions, for example, hormones, pharmaceuticals, alcohols, other substance treatments and many more. Metallothionein also plays a role in hematopoietic cell differentiation and proliferation, as well as prevention of apoptosis of early differentiated cells. Induced MT levels were adversely associated with sensitivity to etoposide-induced apoptosis, signifying that MT is a potential negative controller of apoptosis. Yeast metallothionein coordinate much more strongly to Cu+ than Cu2+. Metallothionein is a cytoplasmic protein, in an adult liver, it is localized mainly in the cytoplasm. In human fetus, metallothionein is localized in hepatocyte nuclei.

Topic (additional 250 + 400 words)
250 words

I would like to write my additional 250 words on L-ascorbate oxidase


 * there is not a lot on the article page
 * find out more about function, history, maybe how it is isolated

400 word/ equivalent

Multicopper oxidase


 * describe mechanism (maybe show figure of mechanism)
 * describe active site (maybe show active site as a figure)

L-ascorbate oxidase (contribution)
Ascorbate oxidase is a type of multicopper blue oxidase which are found in higher plants and fungi. Immunohistochemistry of ascorbate oxidase uncovers that it is associated with the cell wall and cytoplasm.

Ascorbate oxidase is a dimeric enzyme containing two subunits. Ascorbate oxidase has a molecular weight of around 140,000 and contains 8-10 copper atoms per molecule. It is also the largest multicopper blue oxidase.

An ascorbate oxidase protein contains two active sites for each molecule. The quaternary structure of ascorbate oxidase contains two duplicate subunits. Each of the subunits contains one active site. They can have mononuclear or trinuclear copper centers.

Ascorbate oxidase can be isolated from vegetables such as squash or cabbage. Ascorbate oxidase can be found in a soil sample, from a fungal strain. They are also present in microorganisms. The effects of apoptotic cell death were tested using sodium L-ascorbate and L-ascorbate oxidase. It was shown that adding ascorbate oxidase removed its cytotoxic activity against the cells.

It catalyzes the oxidation reaction by reducing the oxygen to water.It was discovered that ascorbate oxidase plays an essential monitoring role in some aspects of plant development and survival under stressful conditions. Its biological function is still not fully known.

Multicopper oxidase (contribution)
Figure 1. Shows the mechanism of the multicopper oxidase.

This mechanism shows the reduction of oxygen; this happens in two electron steps fashion. The fully reduced form (1) reacts with oxygen at a very fast rate to produce a peroxy intermediate (2). Oxygen is reduced by two electrons and coordinates to the three coppers’. The negative D94 lowers the redox potential. Next the oxygen-oxygen bond gets cleaved resulting in the native intermediate (3), the oxygen atoms are reduced and all of the copper atoms are oxidized. In the absence of a substrate, the native intermediate decays to the resting oxidized form (4). The resting oxidized form loses a water and goes to the fully reduced form. Otherwise, in the existence of a substrate, the native intermediate goes straight to the fully reduced form, skipping a step. Figure 2. This figure shows the reduction mechanism for nickel water and nickel hydroxide.

Figure 3. This figure shows the active sites for the multicopper oxidases, the blue circles demonstrating the copper atoms.

References


 * 1) Dooley, D. M., Dawson, J. H., Stephens, P. J., & Gray, H. B. (1981). Spectroscopic studies of ascorbate oxidase. Electronic structure of blue copper sites. Biochemistry,20(7), 2024-2028. doi:10.1021/bi00510a044
 * 2) Gaspard, S., Monzani, E., Casella, L., Gullotti, M., Maritano, S., & Marchesini, A. (1997). Inhibition of Ascorbate Oxidase by Phenolic Compounds. Enzymatic and Spectroscopic Studies†. Biochemistry,36(16), 4852-4859. doi:10.1021/bi9616864
 * 3) Heppner, D. E., Kjaergaard, C. H., & Solomon, E. I. (2014). Mechanism of the Reduction of the Native Intermediate in the Multicopper Oxidases: Insights into Rapid Intramolecular Electron Transfer in Turnover. Journal of the American Chemical Society,136(51), 17788-17801. doi:10.1021/ja509150j
 * 4) Mario De Tullio, Mike Guether & Raffaella Balestrini (2013) Ascorbate oxidase is the potential conductor of a symphony of signaling pathways, Plant Signaling & Behavior, 8:3,e23213, DOI: 10.4161/psb.23213
 * 5) Sawao Murao, Homare Itoh, Takahisa Yajima, Yasunori Ozaki, Shigeki Fukuyasu & Takashi Shin (1992) Isolation and Purification of Ascorbate Oxidase from Acremonium sp. HI-25, Bioscience, Biotechnology, and Biochemistry, 56:6, 847-852, DOI: 10.1271/bbb.56.847
 * 6) Strothkamp, K. G., & Dawson, C. R. (1974). Quaternary structure of ascorbate oxidase. Biochemistry,13(3), 434-440. doi:10.1021/bi00700a006
 * 7) Worrall, J. A., & Vijgenboom, E. (2010). ChemInform Abstract: Copper Mining in Streptomyces: Enzymes, Natural Products and Development. ChemInform,41(31). doi:10.1002/chin.201031271
 * 8) Yoon, J., Liboiron, B. D., Sarangi, R., Hodgson, K. O., Hedman, B., & Solomon, E. I. (2007). The two oxidized forms of the trinuclear Cu cluster in the multicopper oxidases and mechanism for the decay of the native intermediate. Proceedings of the National Academy of Sciences,104(34), 13609-13614. doi:10.1073/pnas.0705137104