18.2 Nitrogen Excretion and the Urea Cycle Produced in liver Blood Kidney urine.
NITROGEN METABOLISM - University of California, … plants fungi Nitrogen is essential ... How many...
Transcript of NITROGEN METABOLISM - University of California, … plants fungi Nitrogen is essential ... How many...
animals
plants
fungi
Nitrogen is essentialfor all organisms(in amino acids andnucleic acids).
Most of the conversionsbetween organic and inorganicnitrogen are catalyzedby bacterial and archaeal enzymes.
oxidative reductive
ATP NH4+ ADP + Pi GS glu gln NAD+ NADH or Fd(ox) Fd(red) GOGAT glu -KG
Glutamate and glutamine are major –NH2 donors through transaminases e.g., Glu +OAA -KG + Asp
Summary
•Nitrogen enters the biosphere through plants, fungi, but mainly bacteria and archaea
•Plants, fungi, and bacteria reduce nitrate nitrogen to ammonium •Ammonium is incorporated into organic molecules by glutamate
dehydrogenase and glutamine synthase/GOGAT•Other amino acids are formed by transamination•The urea cycle removes nitrogen from ammonia and aspartate
as urea