Biosynthesis and processing of mitochondrial glutaminase
The phosphate-dependent glutaminase is asymmetrically associated with the matrix surface of the inner membrane of rat renal mitochondria. The glutaminase contained within intact mitochondria consists of two peptides that are structurally related. However, in vitro translation of renal poly(A/sup +/)RNA yields a 72 kDa protein that is precipitated by glutaminase specific IgG. HTC hepatoma cells and primary cultures of renal proximal tubular cells were used to determine if the 72 kDa protein is a precursor of the mitochondrial glutaminase. When the cells were incubated with (/sup 35/S)methionine for < 3 min. the predominant immunoprecipitable glutaminase has a M/sub r/=72 kDa. With longer periods of incubation, labeled peptides of M/sub r/ = 68 and 65 kDa were also immunoprecipitated. When cells were pulse labeled in the presence of 5 ..mu..M CCCP, a mitochondrial uncoupler, only the 72 kDa protein is formed. When chased with 10 mM methionine and 10 mM cystamine, an antagonist of CCCP, the 72 kDa protein is processed to the 68 and 65 kDa peptides. This process occurs rapidly at 37/sup 0/C, but is slowed considerably at 10/sup 0/C. Quantitative fluorographic analysis of the immunoprecipitated and separated peptides should establish the temporal sequence and kinetics of formation of the processed forms of the glutaminase. Further studies will be conducted to determine the structural difference between the two peptides and their functional significance.
- Research Organization:
- Univ. of Pittsburgh, PA
- OSTI ID:
- 6374671
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AMIDASES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOSYNTHESIS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYMES
EVEN-ODD NUCLEI
FRACTIONATION
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
KIDNEYS
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
MEMBRANES
METHIONINE
MITOCHONDRIA
MOLECULAR STRUCTURE
NON-PEPTIDE C-N HYDROLASES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOIDS
ORGANS
PEPTIDES
PRECURSOR
PROTEINS
RADIOISOTOPES
RATS
RODENTS
SEPARATION PROCESSES
SULFUR 35
SULFUR ISOTOPES
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES