Biomaterial Database

Malate dehydrogenases in phototrophic purple bacteria. Thermal stability, amino acid composition and immunological properties. 1988

M A Tayeh, and M T Madigan

Department of Microbiology, Southern Illinois University, Carbondale 62901.

Purified malate dehydrogenases from four species of non-sulphur purple phototrophic bacteria were examined for their heat-stability, amino acid composition and antigenic relationships. Malate dehydrogenase from Rhodospirillum rubrum, Rhodobacter capsulatus and Rhodomicrobium vannielii (which are all tetrameric proteins) had an unusually high glycine content, but the enzyme from Rhodocyclus purpureus (which is a dimer) did not. R. rubrum malate dehydrogenase was extremely heat-stable relative to the other enzymes, withstanding 65 degrees C for over 1 h with no loss of activity. By contrast, malate dehydrogenase from R. vannielii lost activity above 35 degrees C, and that from R. capsulatus above 40 degrees C. Amino acid compositional relatedness and immunological studies indicated that tetrameric phototrophic-bacterial malate dehydrogenases were highly related to one another, but only distantly related to the tetrameric enzyme from Bacillus. This suggests that, despite differences in their thermal properties, the tetrameric malate dehydrogenases of non-sulphur purple bacteria constitute a distinct biochemical class of this catalyst.

UI	MeSH Term	Description	Entries
D008291	Malate Dehydrogenase	An enzyme that catalyzes the conversion of (S)-malate and NAD+ to oxaloacetate and NADH. EC 1.1.1.37.	Malic Dehydrogenase,NAD-Malate Dehydrogenase,Dehydrogenase, Malate,Dehydrogenase, Malic,Dehydrogenase, NAD-Malate,NAD Malate Dehydrogenase
D005779	Immunodiffusion	Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.	Gel Diffusion Tests,Diffusion Test, Gel,Diffusion Tests, Gel,Gel Diffusion Test,Immunodiffusions,Test, Gel Diffusion,Tests, Gel Diffusion
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
D001419	Bacteria	One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.	Eubacteria
D012241	Rhodopseudomonas	A genus of gram-negative, rod-shaped, phototrophic bacteria found in aquatic environments. Internal photosynthetic membranes are present as lamellae underlying the cytoplasmic membrane.
D012247	Rhodospirillum rubrum	Vibrio- to spiral-shaped phototrophic bacteria found in stagnant water and mud exposed to light.