DNA/RNA/Protein Molecular Weight Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t7-015

Effect

Computation or source lookup only

Input and validation requirements

The specification does not define validation behavior for a zero-length sequence or unknown residues, so a direct lookup implementation can return a chemically misleading water-only result or propagate an undefined mass. It also does not state a default for monoisotopic versus average masses or an explicit DNA-versus-RNA default, allowing materially different outputs.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "sequence": "A",
    "sequence_type": "protein",
    "mass_mode": "average",
    "termini": "free_NH2_and_COOH"
  },
  "expected_outputs": {
    "MW_Da": 89.09408
  },
  "reference_data": {
    "residue_masses_Da": {
      "A": {
        "value": 71.0788,
        "source_convention": "IUPAC standard atomic weights; widely tabulated standard amino-acid residue value"
      }
    },
    "terminal_adjustment_H2O_Da": {
      "value": 18.01528,
      "source_convention": "IUPAC/CODATA widely tabulated average molecular mass of water"
    },
    "known_entry": "Free alanine average molecular weight = 89.09408 Da under residue-plus-H2O convention",
    "source_convention": "Widely tabulated standard biochemical amino-acid molecular-weight convention"
  },
  "working": "A residue = 71.0788 Da. Add the terminal water adjustment: 71.0788 + 18.01528 = 89.09408 Da. This lands exactly on the widely tabulated average molecular weight of alanine under this convention."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json