Reference no: EM132761505

1.Brain cells take up tryptophan, which is then converted to 5-hydroxytryptophan by tryptophan hydroxylase. Aromatic amino acid decarboxylase then catalyzes the formation of the potent neurotransmitter 5-hydroxytryptamine, also called serotonin. In the blood, tryptophan is freely diffusible. The rate of tryptophan concentration is normally well below that of the Km for tryptophan hydroxylase. Aspirin and other drugs displace tryptophan from albumin, thereby increasing the concentration of free tryptophan.

a. What cofactor is required for the activity of tryptophan hydroxylase?

b. Dietary deficiencies in pyridoxine and related metabolites can induce a number of symptoms, including those that appear to be related to derangements in serotonin metabolism. What enzyme could be affected by a deficiency of vitamin B6?

c. What effect does aspirin have on tryptophan metabolism in brain cells?

2.Mature erythrocytes(red blood cells) metabolize glucose at a high rate. In response to the increased availability of glucose, erythrocytes generate lactate and also evolve carbon dioxide.

a. Why is generation of lactate necessary to ensure the continued utilization of glucose?

b. In erythrocytes, what pathway is likely to be used for the generation of carbon dioxide from glucose? Can glucose be completely oxidized to CO2 in erythrocytes? Explain. c. For individuals with a condition known as G6PD deficiency (glucose-6-phosphate dehydrogenase deficiency), their erythrocytes have a high tendency to haemolyze when the individual is exposed to offending drugs or food. Why?