Catabolic end product of purines is
Uric acid
Purine Catabolism Explained
Purines are essential nitrogen-containing compounds that are building blocks of DNA and RNA (Adenine and Guanine). Like other biological molecules, purines undergo metabolism in the body, which includes both synthesis (anabolism) and breakdown (catabolism).
Catabolic Pathway of Purines
The catabolism of purines involves a series of enzymatic reactions that break them down into simpler compounds for excretion. In humans and other primates, the primary pathway leads to the formation of uric acid.
Here's a simplified look at the process:
- Adenine is converted to Hypoxanthine.
- Guanine is converted to Guanine.
- Hypoxanthine and Guanine are further converted to Xanthine.
- Xanthine is then oxidized to Uric acid.
The enzyme Xanthine oxidase plays a crucial role in the conversion of Hypoxanthine to Xanthine and Xanthine to Uric acid.
Uric Acid: The Final End Product
In humans, the final catabolic end product of purines is Uric acid. This uric acid is then transported through the bloodstream to the kidneys, where it is primarily excreted in urine.
Examining Other Potential End Products
- Allantoin: In most other mammals (excluding primates), uric acid is further broken down by the enzyme Uricase into Allantoin, which is more soluble than uric acid and easily excreted. Humans lack a functional Uricase enzyme.
- Urea: Urea is the main nitrogenous waste product resulting from the metabolism of amino acids via the urea cycle, not directly from purine catabolism.
- Xyloric acid: This is not a recognized end product of purine metabolism.
Therefore, when considering the catabolic end product of purines specifically in humans, Uric acid is the correct answer.
Important Questions from Conformation of Proteins and Nucleic acids
Which one of the following statements is true regarding amino acids?
A form and Z form of double stranded DNA differ in the handedness of their helices, nucleotide sequences, and configuration of base to sugar. Based on these properties, which one of the following statements defines a correct combination for A and Z forms of DNA?
The following statements are made
A. B form of DNA has ~10 base pairs/turn and A form of DNA has ~2.3Å helix rise per base pair
B. Both the A and B form of DNA have wider major groove and narrow minor groove
C. The crystalline nature of cellulose is brought about by α (1 → 4) linkage between the glucose subunits.
D. The double bonds in natural lipids are always cis, which provides fluidity to the plasma membrane.
Which of the following combinations represent the correct statements?
Analysis of a homotetrameric protein and a double stranded DNA (that had been incubated in standard buffer) on native gels revealed that they migrated true to their physical states (tetrameric nature of the protein and double stranded nature of the DNA). Following hypotheses were made for the effect of adding high salt to the incubation mix and subsequent analysis on native gels.
A. The protein would migrate as a homotetramer and DNA in double stranded form.
B. The protein would migrate as a monomer but DNA in double stranded form.
C. The protein would migrate as a homotetramer but the DNA in single stranded form.
D. The protein would migrate as a monomer and the DNA in single stranded form.
Which of the following combination of hypotheses is most likely?
Heating of some nucleic acids shows an increase in the absorbance at 260 nm (A260) typified by the plot shown above. The sharp transition midpoint is defined as melting temperature (Tm). Which one of the following nucleic acid samples is NOT expected to generate such a typical profile upon heating of its solution?
