Structural properties of pyruvate carboxylases from chicken liver and other sources
Varieties of pyruvate carboxylase (pyruvate: CO/sub 2/ ligase (ADP-forming), EC 6.4.1.1) obtained from the livers of several species of vertebrates, including humans, all show the same basic structure. They are composed of large polypeptide chains of molecular weights ranging from 1.2 to 1.3 x 10/sup 5/ for the different varieties of the enzyme. The native form of the enzyme appears to be a tetramer with a molecular weight of about 5 x 10/sup 5/. In the case of pyruvate carboxylase from chicken liver each polypeptide chain contains a biotin moiety, thus supporting the thesis that the tetramer contains four identical polypeptide chains. Pyruvate carboxylase from yeast appears to be basically similar to those from the vertebrate species and has a tetrameric structure. Each protomer contains a single polypeptide chain with a molecular weight of 1.25 x 10/sup 5/. In contrast, pyruvate carboxylase from two bacterial species, Pseudomonas citronellolis and Azotobacter vinelandii, appears to be a dimer with a molecular weight (2.5 x 10/sup 5/) about half that of the animal and yeast species. As a further difference, each of the protomers of the bacterial enzymes contain two polypeptides of 6.5 and 5.4 x 10/sup 5/ molecular weight in the case of the Pseudomonas enzyme. The larger of the two polypeptides contains the biotin moiety. The functional units of the bacterial enzyme thus appear to contain two polypeptides while that of the liver and yeast enzymes is made up of a single chain. Neither of these arrangements corresponds with those of other biotin enzymes whose structure has been extensively studied (acetyl-CoA carboxylases from liver or Escherichia coli, and transcarboxylase from Propionibacterium). (auth)
- Research Organization:
- Case Western Reserve Univ., Cleveland, OH (United States)
- OSTI ID:
- 7366937
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 72:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBOXYLASE
MOLECULAR STRUCTURE
POLYPEPTIDES
MOLECULAR WEIGHT
AZOTOBACTER
BIOTIN
CHICKENS
LIVER
PSEUDOMONAS
YEASTS
ANIMALS
AZOLES
BACTERIA
BIOMASS
BIRDS
BODY
CARBOXYLIC ACIDS
DIGESTIVE SYSTEM
ENERGY SOURCES
ENZYMES
FOWL
FUNGI
GLANDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IMIDAZOLES
LYASES
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PEPTIDES
PLANTS
PROTEINS
RENEWABLE ENERGY SOURCES
VERTEBRATES
VITAMIN B GROUP
VITAMINS
550200* - Biochemistry