hsit miage shosw itccmylophy ixt.cityo
hsit eiamg ohsws atth teh blupiud of dPTA inbihits RNR bdoit(rloeenuci reua,)tcesd wchih inhbitsi the rets dNTP yshssni.te
osnub amgei hswos NRR si het rtgtae fo dua.hrrexyyo
I ddi ton owkn het hnmiscame fo hwo TAdP is h,mrufla haluhgto I knwe atth ti saw o.lxtmhcoiyp Yuo acn chekc out U rwlod unqioets :ID 13952 rfo a rpytet good aitlpnnexao
If uoy ujts medeerrbme eht tfca atht RRN csevrnot deruoiensbcotli ot yotebioosedn,cxludeir it sekma snese htta sxeces TAPd (a odb)iyoeunoreclixdet olwud iibnthi hte ezmyne
toG shti gwonr, tub wnhe igkoonl ihst ,pu I was tath SDCI is iosceatasd with a clak fo ionenadse amieansed -g&;t- nuolcimctaau fo naseeion,d cwhih si loioxpyhm.tc-
ADA def causes increase of dATP which strongly inhibits ribonucleotide reductase, reducing dNTP needed for DNA synthesis.
This would particularly effect lymphoid proliferation and function that relies heavily on nucleotide biosynthesis. Half of the cases of neonatal onset of SCID are due to ADA def.
So I missed this question and I was very confused at first as to why. When I first read this question, I thought of Cladribine. Cladribine (Hairy Cell Leukemia ttx) is an adenosine deaminase inhibitor. Cladribine inhibits DNA polymerase, and I chose DNA Polymerase I as my option. Why was I wrong?
Because DNA polymerase I is the prokaryotic DNA poly, not in human lymphocytes. I glanced over the "I" when I was taking this test. If you see this question on your exam, and DNA polymerase is an option - THATS the answer, but ribonucleotide reductase would be a more indirect inhibitor of DNA.
The question also asks for DNA synthesis specifically, which further suggests RR.
These NBMEs do be tricky.