QC Ware and IonQ Mapped Four Orbitals of a Cytochrome P450nor Active Site Onto Eight Qubits of IonQ Forte on 1 September 2026

Quentir Medicine Monitor

Evidence-based insights for quantum medicine.

How tightly a candidate binds its target is one important factor in whether a drug works, and metal centers are among the difficult cases to calculate: an iron atom sitting in the middle of an enzyme. On 1 September 2026 QC Ware and IonQ said they had measured a four-orbital slice of one such site on a quantum computer and landed close to the classical answer. QC Ware's Promethium platform did the classical preparation, IonQ's Forte trapped-ion processor took the quantum measurement through Amazon Braket, and the target was the heme active site of cytochrome P450nor. The workflow calculated an electrostatic interaction energy within 0.5 kcal/mol of classical benchmarks, roughly four percent, inside the one kcal/mol threshold conventionally called chemical accuracy.

The IonQ half of a workflow already run on IBM hardware

This is a follow-up. On 7 August 2026 this Monitor read the same QC Ware Promethium workflow running a nitric oxide reductase calculation on IBM's 156-qubit Heron processor. The platform, the enzyme family and the hybrid division of labor are unchanged; the processor underneath is what is new, which makes hardware portability the company's actual claim. Portability is not comparability: the August disclosure carried no numerical result that today's figure could be set against. Today's release adds four disclosures the August account did not carry: the 115-atom active-site model, its more than 1,000 molecular orbitals, the reduction to a four-orbital active space mapped onto eight qubits, and the 0.5 kcal/mol comparison itself.

What the quantum machine actually did

The quantum step ran on eight qubits of a 36-qubit machine, measuring a four-orbital slice carved out of a model containing more than a thousand molecular orbitals. Promethium built the model, identified the strongly correlated region, reduced it automatically to that active space, and computed the final interaction energies classically after Forte measured the qubits in a single basis. Everything before and after the quantum slice happened on classical hardware.

Which enzyme, and why the framing needs care

P450nor sits in the cytochrome P450 superfamily whose monooxygenase members carry out most human drug metabolism, and the release says exactly that. P450nor itself is something else: a fungal CYP55 nitric oxide reductase, characterized in Fusarium oxysporum among other fungi, reducing nitric oxide to nitrous oxide and taking its electrons straight from reduced nicotinamide adenine dinucleotide, NADH. The release names no organism and no accession. It is a well-characterized computational test case, which is a good reason to choose it for a hardware demonstration and a poor reason to describe the run as modeling human drug metabolism.

What the result can and cannot establish

The comparison target was a classical benchmark, so the classical answer existed first, and the companies report agreement for this known case. The announcement names no preprint, reports no shot count, gives no uncertainty on the 0.5 kcal/mol figure and does not identify which classical method produced the benchmark.