In the mammalian CNS there is a pyridoxal phosphate...

4. In the mammalian CNS there is a pyridoxal phosphate dependent glutamate decarboxylase that catalyzes the conversion of glutamate to gamma-amino butyric acid (GABA). This is an important inhibitory neurotransmitter. (see attachment) GABA is subsequently degraded through transamination to succinic semialdehyde, with alpha- ...continues

In order to determine the major pathway of glycine degradation

In order to determine the major pathway of glycine degradation, you devise an experiment in which mice are fed 13C(alpha)-labeled glycine, and the livers are then isolated and radioactive intermediates detected by GC-MS. Interestingly, you find that the amino acid serine contains the most radioactivity, and that both the Calpha ...continues

Oxidation of palmitate

Estimate the amount of energy a mammal can obtain from the oxidation of palmitate, in the liver under conditions of ketosis, relative to the amount obtainable under conditions of a balanced diet with adequate consumption of glucogenic fuels.

GRE subject question

Sugars in solution have the ability to rotate plane polarized light in proportions to their concentration. The specific rotation of a solution of a mixture of sugars is the weight average of the specific rotations of the individual components. The specific rotation , [α]20,D, for the α and β anomers of D-galactose ...continues

ATCase, CTP, ATP questions

1. In E. coli, ATCase is inhibited by CTP and is activated by ATP. Explain the biological significance of these effects. 2. Explain how PALA can act as both an activator and an inhibitor of ATCase.

Ionization State; Cooperative Ligand Binding

1. The active site of lysozyme contains two amino acid residues essential for catalysis: Glu35 and Asp52. The pka values of the carboxyl side chains of these low residues are 5.9 and 4.5 respectively. a) what is the ionization state(protonated or deprotonated) of each residue at pH5.2, the pH pH optimum of lysozyme? b) how can ...continues

Isomerization Reaction - Ratio; Steady State Concentrations; Cellular Conditions

Consider the isomerization reaction between glucose-6-phosphate and fructose-6-phosphate. A) What is the ratio of fructose-6-phosphate to glucose-6-phosphate under standard conditions? B) Under typical cellular conditions, the steady state concentrations of glucose-6-phosphate and fructose-6-phosphate are 0.083mM and 0.01 ...continues

Reactions - Inhibit; Catalyse; Glycolosis

Why is it advantageous for citrate, the product of reaction 1 of the TCA, to inhibit phosphofructokinase, which catalyses the third reaction in glycolysis? PLEASE EXPLAIN

Reaction; Control Point; Citric Acid Cycle

The Δ G'˚ for the fumerase reaction is -3.4kJ/mol, but Δ G' is near 0. What is the ratio of fumarate to malate under cellular conditions at 37.0C? Is this reaction likely to be a control point in the citric acid cycle? Please Explain

Glucose as Intravenous Food Source

Glucose is frequently administered intravenonusly to patients as a food source. A new resident at the hospital suggests administering glucose-6-phosphate instead. Glucose-6-phosphate requires ATP and you consider the possibility that administering glucose-6-phosphate might save the patient energy. Should you use the resident ...continues