Open AccessOrnithine cycle in Nostoc PCC 73102: presence of an in vitro functional argininosuccinate lyase
Author(s) -
Troshina Olga,
Jansson Eva,
Lindblad Peter
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb10411.x
Subject(s) - argininosuccinate lyase , arginase , ornithine , nostoc , biochemistry , argininosuccinate synthase , citrulline , urea cycle , arginine , enzyme , in vitro , biology , biosynthesis , chemistry , cyanobacteria , amino acid , bacteria , genetics
The presence of argininosuccinate lyase (ASL), an enzyme catalyzing the final step of arginine biosynthesis, was demonstrated in the heterocystous cyanobacterium Nostoc PCC 73102 by measuring in vitro enzyme activity and by visualization of ASL in native protein gels. Activity staining of a native PAGE gel revealed one ASL‐dependent band with a molecular mass of about 240 kDa. A colorimetric assay for ASL based on the measurement of urea produced from arginine in the presence of an excess of arginase was further used to analyze the cyanobacterial ASL. The in vitro ASL activity was highest in cells in exponential growth phase and decreased significantly during the stationary phase of growth, ranging from 4.4 to 0.8 nmol of product formed (mg protein) −1 min −1 . Including arginine, citrulline or ornithine in the growth medium resulted in no significant change in the ASL activities, indicating that Nostoc PCC 73102 ASL is not regulated by metabolites of the ornithine cycle.