Biosynthesis and Degradation Flashcards
Differentiate between the De novo and salvage pathways
De novo - means from the new - taking basic precursors to assemble a brand-new molecule. It is a longer pathway and is more complicated.
Salvage - taking premade/salvaged molecules to assemble a new molecule
What are the parent purine nucleotides of nucleic acids?
Adenosine-5’-monophosphate (AMP)
Guanosine-5’-monophosphate (GMP)
Describe a general De novo pathway.
taking basic precursors to assemble a brand-new molecule
Where does De novo purine nucleotide biosynthesis begin?
The molecule phosphoribosyl pyrophosphate (PRPP)
What happens in the first step of purine nucleotide biosynthesis?
An amino group is donated by glutamate and this group is then attached to carbon #1 of PRPP
What results from the first step of purine nucleotide biosynthesis?
5-phosphoribosyl amine
5’-phosphoribosyl amine is extremely _______ with a half life of _______ at __________
Unstable
30 seconds
At pH of 7.5
What structure is the purine ring built upon?
5’-phosphoribosyl amine
What parts come together to formthe first purine ring?
Aspartate
CO2
Glycine
Formate
Amine nitrogen of glutamine
Draw the structure of the first purine ring.
Where does the nitrogen on the left come from?
Asparate
Draw the structure of the first purine ring.
Where does the carbon at the of the left ring come from?
CO2
Draw the structure of the first purine ring.
Where do the two nitrogens at the base originate?
Amide nitrogen of glutamine
Draw the structure of the first purine ring.
Where do the bottom carbons (one in each ring) come form?
Formate
Draw the structure of the first purine ring.
What molecules come from glycine?
The carbons in the bridge and the top nitrogen in the five-members ring
What is the first intermediate in the De novo purine pathway to have a complete purine ring?
Insinate (IMP)
What molecules are made from inosinate?
AMP and GMP
Know the structure of IMP
What does IMP, AMP, GMP stand for? What are they?
Inosine monophosphate = inosinate
Adenosine monophosphate = adenylate
Guanosine monophosphate = guanylate
What are pyrimidine nucleotides synthesized from?
Aspartate
PRPP
Carbamoyl phosphate
What is a major difference in de novo purine and de novo pyrimidine biosynthesis?
The pyrimidine ring is made first then it is attached to ribose-5-phosphate
??
What are the products of pyrimidine biosynthesis pathway?
Cytidine-5’-monophosphate (CMP)
Uridine-5’-monophosphate (UMP)
What does the prime symbol indicate?
The atom is in the sugar
What does it indicate if there is not a prime written?
The atom is not in the sugar
What are the precursors to deoxyribonucleotides?
Ribonucleotides
What catalyzes the reduction of NDP to dNDP?
Ribonucleotide reductase
Ribonucleotides are the precursors of __________
Deoxyribonucleotides
What does ribonucleotide reductase do?
Catalyzes the reduction of NDP to dNDP
What is produced from the multi-step purine degradation pathway?
Uris acid
What does pyrimidine degradation produce?
Urea
What is formed from the degradation of nucleotides?
Free purine and pyrimidine bases
What happens to the freed purine and pyrimidine bases?
They are salvaged and reused to form ‘new’ nucleotides by much simpler reactions than required by De novo synthesis.
What is an example of salvage pathway assembly of a purine ring? What are the final products?
Adenine + PRPP -> AMP + PPi
Fully assembled purine and pyrophosphate on the side
What catalyzes the salvage pathway production of AMP from premade adenosine? What if you were making GMP from guanosine?
Adenosine phosphoribosyltransferase
Guanosine phosphoribosyltransferase
