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Lecture 23

BIOL 355 Lecture 23: Lecture 23

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BIOL 355
Dr.Cheryl Duxbury

Lecture 23 Effects on molecules: While trying to stabilize, free radicals will attack and modify other molecules, altering their shape and function DNA nucleotide substitutions, single strand breaks and crosslinks evidence of free radical damage to DNA in human breast cancer cells DNA causes mutations in DNA free radicals attack DNA gene damage cancer could be responsible for damage and mutation to DNA with age researchers found OH* free radicals inflict severe damage to DNA in breast tissue appears to impair ability of DNA to construct healthy cells could some breast cancers be due to free radicals with age? Breast cancer: excess production of free radicals andor deficiency of the antioxidant defence system can result in oxidative stress, causing damage to DNA and other molecules over time, such damage may become irreversible and may lead to diseases such as cancer there is evidence showing that oxidative stress and lipid peroxidation are linked to the etiology of breast cancer Proteins proteins can become oxidized (lose an electron) no longer functional amino acids with thiol groups (SH) are easily oxidized could alter the proteins conformation and function Example: S shaped protein functional a free radical comes in and steals an electron and the proton Another free radical comes in and steals an electron and the proton Molecules leave with the 2 electrons and 2 H+ No longer free radicals since they have stabilized themselves stealing an electron from the protein Cshaped protein is nonfunctional Basically they crosslink by oxidizing and forming AGE. Free radicals cause this. Age, there is a 23 fold in oxidized proteins In the of crosslinks of protein (AGEfree radicals) Proteins that are oxidized with age also usually become inactive
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