**because all natural foods that we consume have nucleotides in them
Nucleosides are then degraded by _____
These products are converted to XANTHINE by ____ and ____
Purine nucleoside phosphorylase (PNP)
Guanine deaminase & xanthine oxidase
inosine —> hypoxanthine
hypoxanthine (or PNP product) —> uric acid
**target enzyme for gout treatment to prevent production of uric acid
AMP —> ? —> ? —> ?…
OR
AMP —> Adenosine —> Inosine
**can be deaminased and dephosphorylased in either order
Inosine —> Hypoxanthine —> uric acid
How many enzymes from AMP –> IMP?
AMP –> IMP = one enzyme (when breaking down nucleotides)
Birds, reptiles and insects excrete ____ as their major N excretory compound
Urea (MOST for humans and primates)
Uric acid (MOST for birds, reptiles)
Drug treatment?
–urate crystals may appear in kidney stones and obstruct urinary tract
allopurinol, inhibits Xanthine Oxidase from making uric acid from hypoxanthine
In what tissue is this process particularly important?
Contraction of SKELETAL MUSCLE: as AMP builds up, it is converted IMP then back to AMP with release of fumarate which provides more substrate for TCA cycle and stimulates oxidative metabolism for more energy
Presentation?
-severe, crippling arthritis due to accumulation of uric acid
-retardation
-self-mutilation/aggression
adds ribose onto hypoxanthine (using alpha-PRPP) and converts to IMP or GMP
30% of SCID patients lack the enzyme ______.
In the absence of this enzyme, deoxyadenosine is not deaminated to ______ as normal
adenosine deaminase
deoxyinosine