Urine [delta]-aminolevulinic acid (ALA) concentration was increased at 96.9 mmol/mol of creatinine (reference interval <3.9 mmol/mol creatinine), porphobilinogen (PBG) concentration was normal at 8 [micro]mol/L (reference interval 0-9 [micro]mol/L), and coproporphyrinogen
III concentration was increased at 91.8 nmol/mmol of creatinine (reference interval 2.9-19.3 nmol/mmol of creatinine).
In the second step, coproporphyrinogen
III is formed from the synthesized ALA, following four reactions in the cytoplasm (Fig.
J was diagnosed with HCP, a type of porphyria caused by a defect in coproporphyrinogen
oxidase that leads to an accumulation of coproporphyrinogen
Further researches on the characteristics of chlorophyll metabolism indicated that the precursors of D-aminolevulinic acid (ALA), porphobilinogen (PBG), uroporphyrinogen III (Urogen III), coproporphyrinogen
III (Coprogen III), protoporphyrin IX (Proto IX), Mg-protoporphyrin IX (Mg-Proto IX) and protochlorophyllide (Pchlide) in chlorophyll biosynthesis in Burley21 were lower than in Maryland609 at vigorous growing period; the activity of D-aminolevulinate dehydratase (ALAD) in Burley21 was 0.43% as compared to Maryland609, but the activity of chlorophyllase in Burley21 was 2.04 times as high as in that of Maryland609.
[25,30] The inhibitory effect of lead acetate on conversion of coproporphyrinogen
III to protoporphyrin IX results in shortening of erythrocyte life span and a decrease in the production of Hb.
In AIP urinary ALA and PBG are markedly elevated, and in VP urinary ALA, PBG and coproporphyrinogen
levels are high.
Pb inhibits the three enzymes responsible for heme synthesis; the heme: D-aminolevulinic acid dehydratase (ALAD), the coproporphyrinogen
decarboxylase and the ferrochelatase .
In the classical pathway UROGEN is then converted into heme via the intermediates coproporphyrinogen
III, protoporphyrinogen IX, and protoporphyrin IX .
The association between a genetic polymorphism of coproporphyrinogen
oxidase, dental mercury exposure and neurobehavioral response in humans.
The steps in the heme synthesis pathway that are most vulnerable to heavy metal inhibition are those that involve the enzymes uroporphyrin decarboxylase (UROD) and coproporphyrinogen
The other 2 acute porphyrias arise from deficiencies later in the pathway: coproporphyrinogen
oxidase in hereditary coproporphyria (HCP) and protoporphyrinogen oxidase in variegate porphyria (VP).