PORPHYRIN CHEMISTRY AND METABOLISM Flashcards
prophyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at their carbon atoms via ______
methyne bridges
strong red fluorescence are due to the _______ joining the pyrrole rings
double bounds
porphyrins have the ability to form complexes with _______ bound to ____________ atom of pyrrole rings
metal ions
nitrogen
responsible for the green seen in leaves
contains magnesium bound to the nitrogen
chlorophyll
_________ and _________ can also be measured in urine by appropriate calorimetric tests
ALA and PBG
_______ are a group of diseases caused by abnormalities in the pathway of biosynthesis of the various porphyrins
porphyrias
transport of oxygen in blood
hemoglobin
storage of oxygen in muscle
myoglobin
involvement in electron transport chain
cytochrome c
hydroxylation of xenobiotics
cytochrome P450
degradation of hydrogen peroxide
catalase
oxidation of tryptophan
tryptophan pyrrolase
heme is synthesized from ______– and _______
succinyl coa and glycine
type III uroporphyrinogen uses the enzyme
Uroporphyrinogen III synthase
the conversion of coproporphyrinogen III to protoporphyrinogen III happens in the _________
using the enzyme _______
mitochondria
coproporphyrinogen oxidase
the last reaction (8th step) in heme synthesis involves the incorporation of ____________ iron into protoporhyrin III in a reaction catalyzed by _________ (heme synthase)
ferrous iron
ferrochelatase
heme synthesis in most mammalian cells with the exception of ________
mature erythrocytes
hepatic form of ALA synthase
a regulatory enzyme that catalyzes the rate limiting reaction in the synthesis of heme in liver
ALAS1