Extremely low-frequency electromagnetic fields affect lipid-linked carbonic anhydrase.

Abstract

In the last years, the effect of extremely low-frequency electromagnetic fields (ELF-EMF) on the activity of different enzymes were investigated. Only the membrane-anchored enzymes did decrease their activity, up to 50%. In this work, the effect of ELF-EMF on bovine lung membrane carbonic anhydrase (CA) were studied. Carbonic anhydrases are a family of 14 zinc-containing isozymes catalyzing the reversible reaction: CO(2)+H(2)O = HCO(3)(- )+H(+). CA differ in catalytic activity and subcellular localization. CA IV, IX, XII, XIV, and XV are membrane bound. In particular, CA IV, which is expressed in the lung, is glycosyl phosphatidyl inositol-linked to the membrane, therefore it was a candidate to inhibition by ELF-EMF. Exposure to the membranes to a field of 75 Hz frequency and different amplitudes caused CA activity to a reproducible decrease in enzymatic activity by 17% with a threshold of about 0.74 mT. The decrease in enzymatic activity was independent of the time of permanence in the field and was completely reversible. When the source of enzyme was solubilized with Triton, the field lost its effect on CA enzymatic activity, suggesting a crucial role of the membrane, as well as of the particular linkage of the enzyme to it, in determining the conditions for CA inactivation. Results are discussed in terms of the possible physiologic effects of CA inhibition in target organs.

AI evidence extraction

Main findings

Exposure of bovine lung membranes to a 75 Hz ELF magnetic field at different amplitudes produced a reproducible 17% decrease in carbonic anhydrase activity, with a reported threshold of about 0.74 mT. The decrease was independent of time in the field and was completely reversible; solubilizing the enzyme source with Triton eliminated the field effect, suggesting dependence on membrane anchoring/linkage.

Outcomes measured

• Carbonic anhydrase (CA) enzymatic activity (bovine lung membrane CA; CA IV candidate)

Limitations

• In vitro membrane preparation; findings may not translate to in vivo physiology.
• Exposure duration details not provided in the abstract.
• No sample size or number of replicates reported in the abstract.
• Only one enzyme/source (bovine lung membrane CA) described; generalizability unclear.

Suggested hubs

• occupational-exposure (0.2)
  Study involves ELF magnetic field exposure (75 Hz), which can be relevant to occupational ELF contexts, though no specific workplace source is stated.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": 7.4999999999999993429734834737843129914836026728153228759765625e-5,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Carbonic anhydrase (CA) enzymatic activity (bovine lung membrane CA; CA IV candidate)"
    ],
    "main_findings": "Exposure of bovine lung membranes to a 75 Hz ELF magnetic field at different amplitudes produced a reproducible 17% decrease in carbonic anhydrase activity, with a reported threshold of about 0.74 mT. The decrease was independent of time in the field and was completely reversible; solubilizing the enzyme source with Triton eliminated the field effect, suggesting dependence on membrane anchoring/linkage.",
    "effect_direction": "harm",
    "limitations": [
        "In vitro membrane preparation; findings may not translate to in vivo physiology.",
        "Exposure duration details not provided in the abstract.",
        "No sample size or number of replicates reported in the abstract.",
        "Only one enzyme/source (bovine lung membrane CA) described; generalizability unclear."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "ELF-EMF",
        "extremely low-frequency",
        "75 Hz",
        "magnetic field",
        "0.74 mT",
        "carbonic anhydrase",
        "CA IV",
        "membrane-anchored enzyme",
        "bovine lung",
        "enzyme inhibition",
        "reversible effect",
        "Triton solubilization"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.200000000000000011102230246251565404236316680908203125,
            "reason": "Study involves ELF magnetic field exposure (75 Hz), which can be relevant to occupational ELF contexts, though no specific workplace source is stated."
        }
    ]
}

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