Analysis of protein disintegration under proton bombardment.

• Main Author: Eadie, Frank Stewart.
• Other Authors: Foster, J. (Supervisor)
• Format: Others
• Language: en
• Published: McGill University 1952
• Subjects: Physics.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=124002

Dry bovine serum albumin and bovine haemoglobin have been irradiated with 50 Mev cyclotron protons. The measured dosage rate was 6.1 ± 2.7 x 10^5 rep/second. Irradiation times varied from one to eight minutes. Fragments of gram molecular weight estimated at 1000 were round in sedimentation experiments on serum albumin irradiated with 7.3 x 10^7 rep. These fragments did not absorb at 2920 Å. It was concluded that molecules of serum albumin in which a single primary ionization occurs are broken preferentially at one point to give fragments of this size. Sedimentation experiments on haemoglobin irradiated with dosages of protons up to 3 x 10^8 rep showed that little fragmentation had occurred. For serum albumin, the ultra-violet absorption at 2576 Å and 2920 Å increased by a factor of three after a primary ionisation had occurred in 93% of the irradiated molecules. The absorption of haemoglobin at the same wavelengths increased by 50%. These changes were attributed to a shift in the maximum absorption band towards the visible end of the spectrum. At 3906 A the absorption of haemoglobin decreased by 50%.