Non-thermal effects of microwaves on proteins: thermophilic enzymes as model system.

PAPER pubmed FEBS letters 1997 In vitro study Effect: harm Evidence: Low

Read original paper → DOI: 10.1016/s0014-5793(96)01505-0 PMID: 9037175 Evidence Lab

Abstract

Two thermophilic and thermostable enzymes, isolated from Sulfolobus solfataricus, S-adenosylhomocysteine hydrolase and 5'-methylthioadenosine phosphorylase, were exposed to 10.4 GHz microwave radiation in order to discriminate between thermal and non-thermal microwave effects. The exposure causes a non-thermal, irreversible and time-dependent inactivation of both enzymes; the inactivation rate is related to the energy absorbed and is independent of the enzyme concentration. The influence of salts on enzyme inactivation has also been investigated. Conformational changes of S-adenosylhomocysteine hydrolase, detected by fluorescence and circular dichroism techniques, suggest that microwaves induce protein structural rearrangements not related to temperature.

AI evidence extraction

At a glance

Study type

In vitro study

Effect direction

harm

Population

—

Sample size

—

Exposure

microwave · 10400 MHz

Evidence strength

Low

Confidence: 74% · Peer-reviewed: yes

Main findings

Two thermophilic enzymes (S-adenosylhomocysteine hydrolase and 5'-methylthioadenosine phosphorylase) exposed to 10.4 GHz microwave radiation showed non-thermal, irreversible, time-dependent inactivation. The inactivation rate was related to absorbed energy and independent of enzyme concentration; conformational changes detected by fluorescence and circular dichroism suggested microwave-induced structural rearrangements not related to temperature.

Outcomes measured

enzyme activity/inactivation
protein conformational/structural changes (fluorescence, circular dichroism)
influence of salts on inactivation

Limitations

No exposure duration reported in abstract
No SAR or dosimetry details reported in abstract beyond 'energy absorbed'
In vitro enzyme model; relevance to whole organisms/humans not addressed in abstract
Sample size/replicates not reported in abstract

Suggested hubs

mechanisms-non-thermal (0.86)
Reports non-thermal microwave effects on protein structure and enzyme activity.

View raw extracted JSON

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 10400,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "enzyme activity/inactivation",
        "protein conformational/structural changes (fluorescence, circular dichroism)",
        "influence of salts on inactivation"
    ],
    "main_findings": "Two thermophilic enzymes (S-adenosylhomocysteine hydrolase and 5'-methylthioadenosine phosphorylase) exposed to 10.4 GHz microwave radiation showed non-thermal, irreversible, time-dependent inactivation. The inactivation rate was related to absorbed energy and independent of enzyme concentration; conformational changes detected by fluorescence and circular dichroism suggested microwave-induced structural rearrangements not related to temperature.",
    "effect_direction": "harm",
    "limitations": [
        "No exposure duration reported in abstract",
        "No SAR or dosimetry details reported in abstract beyond 'energy absorbed'",
        "In vitro enzyme model; relevance to whole organisms/humans not addressed in abstract",
        "Sample size/replicates not reported in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "10.4 GHz",
        "non-thermal effects",
        "thermophilic enzymes",
        "Sulfolobus solfataricus",
        "S-adenosylhomocysteine hydrolase",
        "5'-methylthioadenosine phosphorylase",
        "enzyme inactivation",
        "protein conformational change",
        "circular dichroism",
        "fluorescence"
    ],
    "suggested_hubs": [
        {
            "slug": "mechanisms-non-thermal",
            "weight": 0.85999999999999998667732370449812151491641998291015625,
            "reason": "Reports non-thermal microwave effects on protein structure and enzyme activity."
        }
    ]
}

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AI-extracted fields are generated from the abstract/metadata and may be incomplete or incorrect. This content is for informational purposes only and is not medical advice.

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