THE MECHANISM OF X-RAY INACTIVATION OF PHOSPHOGLYCERALDEHYDE DEHYDROGENASE

Journal Article · Fri Jul 01 04:00:00 EDT 1960 · Intern. J. Radiation Biol.

DOI:https://doi.org/10.1080/09553006014550351· OSTI ID:4136693

Lange, R; Pihl, A

The x ray inactivation of crystalline rabbit-muscle phosphoglyceraldehyde dehydrogenase (GAPDH) in solution was correlated with the concurrent radiochemical destruction of enzyme SH-groups. The inactivation was found to be directiy proportional to the disappearance of enzyme SHgroups and was complete when three SH-groups were destroyed. Exactly the same relationship between enzyme inactivation and disappearance of free SH-groups was found when an increasing number of SH-groups were blocked by the addition of p- chloromercuribenzoate. The data strongly indicate that the x-ray inactivation of GAPDH can be entirely accounted for by destruction of its SH-groups. The G-value for the x-ray destruction of the enzyme SH-groups was found to be 0.23, indicating that the major part of the radiation energy is dissipated in processes not involving the protein SH-groups. Blocking of enzyme SH-groups by p- chloromercuribenzoate prior to the irradiation provided partial protection of the enzyme. The data are consistent with the view that, contrary to current assumptions, all SH-groups of GAPDH are of importance for the enzyme activity. (auth)

• Research Organization: Norsk Hydro's Inst. for Cancer Research, Oslo
• Sponsoring Organization: USDOE
• NSA Number: NSA-14-025330
• OSTI ID: 4136693
• Journal Information: Intern. J. Radiation Biol., Journal Name: Intern. J. Radiation Biol. Vol. Vol: 2
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BIOCHEMISTRY
BIOLOGY AND MEDICINE
ENZYMES
RADIATION EFFECTS
RADIOCHEMISTRY
SULFHYDRYL RADICALS
X RADIATION