Zahra B

Is it true that bicarbonate binds reversibly to the heme moiety of hemoglobin? Or do the heme portion only bind oxygen?

Im correcting some old tests in physiology and came upon the question "Which statements characterize IgM immunoglobulins" One of the alternatives are "it’s a secretory immunoglobulin". Is this correct? I know that the main secretory immunoglobulin is IgA (sIgA) but I found some sources that mention sIgM, though it's not as effective as sIgA. Is it considered a secretory immunoglobulin?

Thank you for answering. I always thought that the side chains were primarily responsible for reactions, but since that is not the case, it makes more sense.

No, not really.

I noticed in my textbook that the synthesis of AMP uses aspartate as a nitrogen source and syntheis of GMP uses glutamine. Why doesn't the synthesis of AMP require asparagine instead of aspartate, since asparagine has a nitrogen group in its side chain? I thought that the reactive part of an AA was the side chain so it doesn't make sense to me.

@studiot Thank you so much for explaining! After reading it 10 times I actually think I got it now 😁

I think i solved it. Don't know if it is correct but it seems reasonable.

Hello! Thank you for taking your time to answer. Just wanted to clarify, this is not a homework, its a question from an old test I found while preparing for my test next week. I believe if we substitute km/2, the linear graph moves to the left since less substrate is needed to half saturate the enzyme? I was also thinking that since substrate concentration is much less than Km, the velocity of the reaction is proportional to the substrate concentration (first order), so maybe the answer should simply be Vo = substrate concentration? Ps. I dont know why but everytime I put the S in brackets, it strikes through the text

The question says "write the formula for calculating velocity of enzymatic reactions. From this formula, calculate the velocity of a reaction with concentration of the substrate equal to 0.5 Km" Im totally stuck. I know the formula is Vo = Vmax (S)/Km + (S) but I cant solve it any further