Introduction Tyrosinase is a copper-containing enzyme that catalyzes oxidation steps in melanin synthesis (Curto, et al.) Tyrosinase and its inhibitors have been studied for cosmetic and medical purposes. By inhibiting tyrosinase activity, skin can be whitened for cosmetic purposes. Inhibiting tyrosinase activity can also be a treatment for disorders involving elevated pigmentation of the skin such as age spots (Heng). Tyrosinase is active between a pH of 6.0 and 7.8. The optimal temperature for tyrosinase activity is 42° C, but the enzyme operates in the range of 25° C to 70° C (Kelly). Tyrosinases have two coupled enzymatic functions. One is cresolase activity, which catalyzes the hydroxylation of monophenols to form o-diphenols. The other enzymatic function is catecholase activity, which oxidizes o-phenols to produce o-quinones. O-quinones are highly reactive and typically polymerize to form melanin (Kelly, et al., Heng, et al). Tyrosinase is the most important enzyme in the melanin production pathway because it catalyzes the rate-limiting step. Tyrosinase is also thought to have other functions in melanin production (Tuskamoto). …show more content…
However, in the presence of DOPA, the lag period should have been diminished enough to be negligible (Packer). If the lag period was present, though, the enzyme would have been less efficient in experiments done earlier, which is consistent the results. The results may also have been affected by the timing of the experiment because tyrosinase is only stable for approximately an hour under these reaction conditions (Heidcamp). It may not be accurate to base the reasons for the results entirely on benzoic acid acting as an inhibitor; the change in results may have also been because of decreased enzyme function. If fewer enzymes were functioning, the enzymes would have reached saturation sooner; this could have caused the decrease in
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MELANOTAN II PRODUCT DESCRIPTION Melanotan II is a lab synthesized peptide hormone that imitates melanocyte-stimulating hormone (a hormone that naturally occurs in the human body). Alpha-MSH (also referred to as α-MSH or alpha-melanocyte-stimulating hormone (MSHs) stimulates the melanogenesis; the process by which the skin and hair darkening pigments are produced in mammals. In vitro administration of Melanotan II has been observed to have excellent portent melanotropic action. The structural name of Melanotan II is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. The molecular formula for Melanotan II is: C50H69N15O9 Melanotan II falls in the class of peptides hormones referred to as Melanocortins.
The products are released from the enzyme surface to regenerate the enzyme for another reaction cycle. The active site has a unique geometric shape that is complementary to the shape of a substrate molecule, similar to the fit of puzzle pieces.
Adapalene is a topical retinoid-like compound, chemically similar to vitamin A, yielding keratolytic effects . It can be used in cobination with antibiotc and azelaic acid in the treatment of acne vulgaris, it can cause skin irritation. HYDROQUINONE; also chemically known as 1,4-dihydroxybenzene, is a ubiquitous chemical that occurs naturally in our environment in wheat, tea, berries, beer and coffee, but is detoxified within the liver into inert compounds , is an effective skin lightener which acts by preventing the synthesis of melanin . It is one if the stongest and most efficacious skin lightening agents. Since hydroquinone dependent melanogenic inhibition requires the presence of active tyrosinase, it is therefore not useful in altering
LABORATORY REPORT Activity: Enzyme Activity Name: Natalie Banc Instructor: Elizabeth Kraske Date: 09.22.2016 Predictions 1. Sucrase will have the greatest activity at pH 6 2. Sucrase will have the greatest activity at 50 °C (122 °F) 3. Sucrase activity increases with increasing sucrose concentration Materials and Methods Effect of pH on Enzyme Activity 1. Dependent Variable amount of product (glucose and fructose) produced 2.
The three things that can cause the enzyme to denature is a large change in pH level, High Temperature, and substrate concentration. According to our knowledge, we know that a large change in pH will cause instability in the protein structure thus resulting in denaturation of the enzyme. From the data, we can see that pH 3 (total:6.3) and 10 (total:6.2) were the slowest because pH 3 is probably the highest acid and pH 10 is the highest base. The highest acid or base pH represents a large change which would cause the enzyme to denature. The fastest pH was 6 (total:34.5), and it seems that there wasn’t a large change which resulted in a stable structure.
These enzymes have a secondary and tertiary structure and this could be affected by increases and decreases in temperature beyond the optimum temperature of the enzyme to work in. Mostly enzymes are highly affected any changes in temperature beyond the enzymes optimum. There are too
ABSTRACT: The purpose of the experiments for week 5 and week 6 support each other in the further understanding of enzyme reactions. During week 5, the effects of a substrate and enzyme concentration on enzyme reaction rate was observed. Week 6, the effects of temperature and inhibitor on a reaction rate were monitored. For testing the effects of concentrations, we needed to use the table that was used in week 3, Cells.
By observing figure 3, the more enzyme that is available, the faster the reaction rate is. The optimal enzyme concentration was chosen based on the R2 values from figure 2. The highest observable rate also had the best R2 number, which was closest to one. This enzyme concentration was used in part 2.
The literature review will begin by constructing a framework defining Melasma and its interventions. According to Hurley, M.E., Guevara, I.L., Gonzales, R.M. and Pandya, A.G., (2002) Melasma is a pigmentation disorder and is common among women of Hispanic and Asian groups arising from biologically active melanocytes, associated with high vascularity in the areas and occurrence of angio-genic factor in the epidermis. At the outset, it is important to understand Melasma as a disorder and explore the reasons for its occurrence. The etiology of melasma has yet to be established, and the course of treatment continues to be a challenge.
Enzymes speed up chemical reactions enabling more products to be formed within a shorter span of time. Enzymes are fragile and easily disrupted by heat or other mild treatment. Studying the effect of temperature and substrate concentration on enzyme concentration allows better understanding of optimum conditions which enzymes can function. An example of an enzyme catalyzed reaction is enzymatic hydrolysis of an artificial substrate, o-Nitrophenylgalactoside (ONPG) used in place of lactose. Upon hydrolysis by B-galactosidase, a yellow colored compound o-Nitrophenol (ONP) is formed.
Introduction: Enzymes are biological catalysts that increase the rate of a reaction without being chemically changed. Enzymes are globular proteins that contain an active site. A specific substrate binds to the active site of the enzyme chemically and structurally (4). Enzymes also increase the rate of a reaction by decreasing the activation energy for that reaction which is the minimum energy required for the reaction to take place (3). Multiple factors affect the activity of an enzyme (1).
Introduction 1.1 Aim: To determine the kinetic parameters, Vmax and Km, of the alkaline phosphatase enzyme through the determination of the optimum pH and temperature. 1.2 Theory and Principles (General Background): Enzymes are highly specific protein catalysts that are utilised in chemical reactions in biological systems.1 Enzymes, being catalysts, decrease the activation energy required to convert substrates to products. They do this by attaching to the substrate to form an intermediate; the substrate binds to the active site of the enzyme. Then, another or the same enzyme reacts with the intermediate to form the final product.2 The rate of enzyme-catalysed reactions is influenced by different environmental conditions, such as: concentration
Bio Chem lab Report 04 Enzyme Biochemistry Group Member: Chan Man Jeun Duncan (16002621) Law Sze Man (16000478) Introduction Enzyme is a protein base structure substance in our body. It works at a biocatalyst that will catalyzing the chemical reaction, which helps to speed up the chemical reaction. Enzyme could only function in specific shape, and the shape of enzyme is depending on the environment, therefore it is hard for an enzyme to function well in an extreme environment. The aim of this experiment is to see can the enzyme functions normally in different environment(pH, temperature and salt concentration) via using starch solution, amylase from saliva, 0.5M HCl solution, 0.5M NaOH solution and NaCl solution, and using iodine solution