Physiological regulation of ribulose 1,5 bisphosphate carboxylase/oxygenase in Rhodospirillum rubrum

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6438976

Cook, L S

Rhodospirillum rubrum employs several mechanisms for regulating the activity of ribulose 1,5 bisphosphate carboxylase/oxygenase (RuBPC/O). The activity of RuBPC/O is modulated at the level of synthesis of the enzyme and also post-transcriptionally by inactivation of the preformed enzyme. The synthesis of RuBPC/O in R. rubrum is greatly influenced by the conditions of culture. Under conditions of carbon dioxide limitation, R. rubrum derepresses the synthesis of RuBPC/O. When growing autotrophically under low CO/sub 2/ (1.5-2%) concentrations, the synthesis of the enzyme is derepressed such that RuBPC/O represents up to 50% of the soluble protein in the cell. These phenomenal levels of enzyme activity are not observed when the culture is supplied with higher levels of CO/sub 2/ (5-6%). The increase in enzyme activity observed in derepressed cultures is not paralleled by an increase in vivo CO/sub 2/ fixation rate. Rhodospirillum rubrum grown in the presence of /sup 32/P-orthophosphate, has radiolabel associated with several proteins. One of these proteins co-migrates with RuBPC/O in a SDS-polyacrylamide gel. The phosphoprotein can be separated from RuBPC/O using the technique of two-dimensional gel electrophoresis. A Western blot does not show any immunological cross-reactivity between the two proteins.

• Research Organization: Texas Univ., Austin (USA)
• OSTI ID: 6438976
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOSYNTHESIS
CARBON DIOXIDE FIXATION
CARBON-CARBON LYASES
CARBOXY-LYASES
CARBOXYLASE
DAYS LIVING RADIOISOTOPES
ELECTROPHORESIS
ENZYME ACTIVITY
ENZYMES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LYASES
MICROORGANISMS
NUCLEI
ODD-ODD NUCLEI
OXIDOREDUCTASES
OXYGEN COMPOUNDS
OXYGENASES
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
RADIOISOTOPES
RHODOSPIRILLUM
SYNTHESIS
TRACER TECHNIQUES