For each of the following structures: 1. Identify the cofactor  2. State the type of reaction or name a specific reaction that the cofactor facilitates. A.                               B.                                    C.   

Upload your answers to these questions. a.) Beginning with PLP (Vit. B6), whose structure is given below, draw out the mechanistic steps that result in the transfer of the amino group of Ala to PLP as catalyzed by the enzyme alanine aminotransferase.  (4 pts.) b.) Draw the structure of the molecule that ultimately accepts the amino group of Ala in the above aminotransferase  reaction. (2 pts.) c.)  The 

Upload an image of your answers to this question. Krabbe disease is a rare degenerative disease that affects the myelin sheath. Individuals who have this disease have levels of psychosine that are elevated on the order of 100 times that of normal individuals. Psychosine is sphingosine with a galactose (epimer of Glc at C-4) attached at the terminal 1 position by a

Upload an image of your answer to these questions. In the liver and to a lesser extent in the cortex of the kidney, glucose is synthesized from pyruvate (gluconeogenesis). Most of the enzymes of glycolysis are used to catalyze the glycolytic reactions in reverse. One of these is the aldolase reaction. Write out the mechanism for the aldolase reaction in reverse to synthesize fructose 1,6-bisphosphate from two different phosphotrioses. Include the structures and names of all substrates and products and note all necessary cofactors, if any.  NOTE: Acceptable abbreviations for compound names and cofactors are ok.

Upload an image of your answer to this question.  There are two cofactors, lipoic acid (the crane), FAD, which are alternately reduced and oxidized in the pyruvate dehydrogenase complex, and NAD+, which is reduced as a final product. Draw the structures of the reduced forms of each of these three cofactors (do not include the Cys amino acid residues associated with the protein). You only need to show the relevant structural ring parts that change when each of these are reduced. (6 pts.)     Reduced form of Lipoic acid         Reduced form of FAD                Reduced form of  NAD+

Upload an image of your answers to this question. Draw the following structures: Oleamide, the simple amide (NH2) of oleic acid has been isolated from the spinal fluid of cats and identified as the molecule responsible for causing sleep. In humans, oleoyl ethanolamide is an endogenous regulator of food intake produced in the intestines and has potential as an anti-obesity drug. Draw the structure of oleic acid. (2 pts.) Anandamide functions as an endogenous ligand of cannabinoid (psychoactive compounds in marijuana) receptors in humans and gets its name from the Sanskrit word, “ananda”, meaning bliss. This compound is the ethanolamine (HO-CH2-CH2-NH2) amide of arachidonic acid. Draw the structure of anandamide. (3 pts.) Saplenic acid 16:1(D10) is the most abundant lipid component of human sebum. Draw the structure of this fatty acid. (2 pts.) Phosphtidylserine is a regulator of apoptosis (programmed cell death, causing a cell to commit “suicide”) in response to calcium-dependent stimuli. Draw a phosphatidylserine of your choice with two different unsaturated fatty acids and give the names of the acids you chose to draw. (3 pts.) Ceramide-1-phosphate is a potent inhibitor of apoptosis or programmed cell death, as well as an inducer of cell survival. Draw the ceramide that has a linolenic acid attached and a phosphate attached at the terminal, 1 position. (3 pts.) A very long chain polyunsaturated fatty acid (VLC-PUFA) is found in a glycerophopholipid associated with the retinal membrane in the eye. This is a phosphtidyl choline compound with DHA (docosahexenoic acid – C-22:6 (D4….) esterified at the 1 position of the glycerol and a C-34:6

This figure shows the fraction or percent of myoglobin or hemoglobin O2 binding sites occupied on the y-axis as a function of O2 partial pressure shot on the x-axis. The middle Hb blue curve is for normal Hb. The right-hand red Hb curve reflects the shift in the bonding affinity of Hb in response to a drop in pH, whereas the left-hand green Hb curve reflects the change in response to an increase in pH.     Diagram citation Wikimedia Commons (Public Domain)  Image Description  Graph depicting hemoglobin oxygen saturation percentage against oxygen partial pressure (mmHg). Three curves represent different pH levels: green for pH 7.8 (alkalosis hypocapnia), blue for pH 7.4 (normal), and red for pH 7.0 (acidosis hypercapnia). The y-axis ranges from 0 to 100%, indicating hemoglobin oxygen saturation, while the x-axis ranges from 0 to 120 mmHg, indicating oxygen partial pressure. The curves show the relationship between oxygen binding and blood pH. Which of these curves shows the greatest affinity for O2? (1 pt.) Which one of the two shifted Hb curves, right or left, would result in the release of the most O2 to the cells, if the lung pO2 decreases from 100 torr to 60 torr and the pO2 of the tissues remains the same at 27 torr? Briefly justify your answer. (2 pts.)

Upload an image of your answers to this question. Draw the structure of the N-terminal residue at pH 12.0.  (2 pts) Draw the structure of the C-terminal residue at pH 1.0 ?  (2 pts.) Draw the principle structure of residue number  2 at pH 5 showing the absolute stereochemical configuration of the L family of amino acids. (3 pts.)

In the procedure above, they mentioned that the purified protein was alkylated. Briefly explain why it might be desirable to treat the reduced protein with iodoacetic acid (ICH2CO2H) before it is subjected to further purification by HPLC. 

Upload an image of your answers to this question. Splenda is a sugar substitute that can be used in cooking, whereas Nutrasweet cannot (It is a dipeptide and is thermally unstable). Splenda is made from D-sucrose by substitution of some of the hydroxyl groups with chlorine atoms. Draw the structure of Splenda given the following information about the hydroxyl groups that have been replaced by chlorine atoms. The hydroxyl groups at carbons 1 and 6 of the sugar in the furanose form and the hydroxyl group at carbon 4 of the sugar in the pyranose form have been replaced by chlorine atoms. The sugar in the pyranose form has the same stereochemical configuration as galactose.   For your interest: A foreign post-doctoral student in Great Britain first prepared Splenda. He misunderstood the word “test” and thought the supervisor said “taste,” so he did (not good chemical practice).  It turned out that this chlorinated derivative of sucrose is 600 times sweeter than sucrose itself.