Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the PPOX gene. Protoporphyrinogen oxidase is responsible for the seventh step in biosynthesis of protoporphyrin IX. This porphyrin is the precursor to hemoglobin, the oxygen carrier in animals, and chlorophyll, the dye in plants.
Table of Contents
What does protoporphyrinogen oxidase do?
Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the PPOX gene. Protoporphyrinogen oxidase is responsible for the seventh step in biosynthesis of protoporphyrin IX. This porphyrin is the precursor to hemoglobin, the oxygen carrier in animals, and chlorophyll, the dye in plants.
What is the substrate of Protoporphyrinogen oxidase?
One of the steps of tetrapyrrole biosynthesis rely on protoporphyrinogen IX oxidase (PPO; EC 1.3. 3.4), which catalyzes the six-electron oxidation of protogen (protoporphyrinogen IX, the substrate) to proto (protoporphyrin IX, the product) in both eukaryotic and prokaryotic organisms (Figure 1) [2], [3].
What is the PPOX gene?
The PPOX gene provides instructions for making an enzyme known as protoporphyrinogen oxidase. This enzyme is involved in the production of a molecule called heme. Heme is vital for all of the body’s organs, although it is most abundant in the blood, bone marrow, and liver.
What is Protoporphyrinogen oxidase in plants?
Protoporphyrinogen oxidase (EC 1–3–3–4) is the penultimate enzyme of the heme biosynthesis pathway and the final enzyme of the common branch of the heme and chlorophyll biosynthesis pathways in plants.
How do PPO herbicides work?
The primary mechanism of action of these herbicides is inhibition of the PPO enzyme which ultimately leads to disruption of cell membranes. The most common visual symptoms of PPO herbicides are leaves that become chlorotic (yellow), then desiccated and necrotic (brown) within 1 to 3 days.
What is variegate porphyria?
Variegate porphyria is a rare genetic metabolic disorder characterized by deficient function of the enzyme protoporphyrinogen oxidase (PPO or PPOX).
How do PPO inhibitors work?
The protoporphyrinogen oxidase (PPO) inhibitors are primarily contact-type, postemergence, broadleaf-weed herbicides, but a few have preemergence soil activity. The primary mechanism of action of these herbicides is inhibition of the PPO enzyme which ultimately leads to disruption of cell membranes.
What are PPO herbicides?
The PPO inhibitor herbicides are primarily foliar-applied and have limited soil activity. They are contact-type herbicides that primarily affect only the sprayed plant tissues. The leaves of susceptible plants will quickly become chlorotic (yellow), then desiccated and necrotic (brown) within one to three days.
What is a Group 14 herbicide?
Group 14 herbicides are inhibitors of the protoporphyrinogen oxidase (PPO) enzyme. There are currently no known populations of weeds resistant to Group 14 in Australia. However, there are 6 weeds with confirmed resistant to Group 14 herbicides elsewhere in the world and in particular in populations of Amaranthus spp.
What is hepatic porphyria?
[1][2] Hepatic porphyrias are those in which the enzyme deficiency occurs in the liver. Hepatic porphyrias include acute intermittent porphyria (AIP), variegate porphyria (VP), aminolevulinic acid dehydratase deficiency porphyria (ALAD), hereditary coproporphyria (HCP), and porphyria cutanea tarda (PCT).