HEME
How many d electrons Fe has in TPPFe-Superoxo
5
What is the bond order of molecular oxygen, TPPFe-superoxo and TPPFe-peroxo
2, 1.5 and 1
The porphyrin ring in heme is composed of how many pyrrole rings?
4
Which form of iron binds oxygen in heme?
Fe2+
Which type of heme protein typically gives an axial EPR signal at g ≈ 6 and g ≈ 2?
High-spin ferric myoglobin
Which oxidation state of iron in heme is EPR-active?
Fe³⁺ (high-spin)
Temperature in EPR measurements of heme proteins is typically kept low to:
Increase signal-to-noise ratio
Which prestigious award did Dr. Wijeratne receive in 2024 to fund his investigations into nitrogen oxide–heme chemistry?
NIH R35 MIRA Outstanding Investigator Award
EPR observations suggest a substrate-bound (low-spin) state in P450 enzymes. What are the g values?
g = 2.4, 2.2, 1.9
What does a rhombic EPR spectrum indicate about a ferric heme center?
Anisotropic (low symmetry) environment
Which test detects porphyrin accumulation in urine?
Watson-Schwartz test
The lab uses cryogenic setups during experiments primarily to:
Preserve reactive intermediates for spectroscopic analysis
Which enzyme catalyzes the breakdown of heme to biliverdin?
Heme oxygenase
Which gas binds to heme with higher affinity than oxygen?
Carbon monoxide
In cytochromes, what is the primary role of heme?
Electron transfer
What key mechanistic process is being probed by the lab’s synthetic model systems involving heme and O₂ or NOₓ?
Dioxygen activation and nitrogen oxide interconversion
Which enzyme catalyzes the rate-limiting step of heme biosynthesis?
ALA synthase (ALAS)
Heme is an essential component of which electron transport chain protein?
Cytochrome c
Which organ is primarily involved in regulating heme synthesis?
Liver
What is the primary research focus of the Wijeratne Lab?
Bioinspired model complexes of heme enzymes activating O₂ and NOₓ