Pathways of assimilation of (/sup 13/N)N/sub 2/ and /sup 13/NH/sub 4//sup +/ by cyanobacteria with and without heterocysts. [Gloeothece sp. , Anacystis nidulans]
The principal initial product of metabolism of (/sup 13/N)N/sub 2/ and /sup 13/NH/sub 4//sup +/ by five diverse cyanobacteria is glutamine. Methionine sulfoximine inhibits formation of (/sup 13/N)glutamine except in the case of Gloeotnece sp., an organism with a thick sheath through which the inhibitor may not penetrate. Thus, glutamine synthetase appears to catalyze the initial step in the assimilation of N/sub 2/-derived or exogenous NH/sub 4//sup +/ by these organisms. (/sup 13/N)Glutamate is, in all cases, the second major product of assimilation of /sup 13/N-labeled N/sub 2/ and NH/sub 4//sup +/. In all of the N/sub 2/-fixing cyanobacteria studied, the fraction of /sup 13/N in glutamine declines and that in glutamate increases with increasing times of assimilation of (/sup 13/N)N/sub 2/ and /sup 13/NH/sub 4//sup +/, and (Gloeothece again excepted) methionine sulfoximine reduces incorporation of /sup 13/N into glutamate as well as into glutamine. Glutamate synthase therefore appears to catalyze the formation of glutamate in a wide range of N/sub 2/-fixing cyanobacteria. However, the major fraction of (/sup 13/N)glutamate formed by Anacystis nidulans incubated with /sup 13/NH/sub 4//sup +/ may be formed by glutamic acid dehydrogenase. The formation of (/sup 13/N)alanine from /sup 13/NH/sub 4//sup +/ appears to be catalyzed principally either by alanine dehydrogenase (as in Cylindrospermum licheniforme) or by a transaminase (as in Anabaena variabilis).
- Research Organization:
- Michigan State Univ., East Lansing
- OSTI ID:
- 5112880
- Journal Information:
- J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 134:1; ISSN JOBAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550700* -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
AMIDES
AMINO ACIDS
AMMONIA
AMMONIUM COMPOUNDS
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BIOSYNTHESIS
CARBOXYLIC ACIDS
CHEMISTRY
DEHYDROGENASES
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
GLUTAMINE
HYDRIDES
HYDROGEN COMPOUNDS
ISOTOPES
LIGASES
LIGHT NUCLEI
METABOLISM
MICROORGANISMS
MINUTES LIVING RADIOISOTOPES
NITROGEN 13
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDOREDUCTASES
RADIOISOTOPES
SYNTHESIS