Degradation of serine-containing oligopeptides by Peptostreptococcus micros ATCC 33270.
OBJECTIVE
Microorganisms of Peptostreptococcus micros are asaccharolytic, anaerobic gram-positive cocci that are frequently isolated from human oral sites such as periodontal pockets. Preliminary study showed that several amino acids, including serine, enhanced slightly the growth of P. micros. Therefore, we investigated the degradation of serine and serine-containing oligopeptides.


METHODS
Metabolic end products were determined with high-performance liquid chromatography. The related enzymatic activities in cell-free extract were also assayed.


RESULTS
Washed P. micros degraded serine-tripeptides (Ser-Ser-Ser), and produced formate, pyruvate, acetate, and ammonia. They also degraded serinyl-tyrosine (Ser-Tyr) to the same products. Related enzymatic activities, such as serine dehydratase, pyruvate formate-lyase, formate dehydrogenase, pyruvate oxidoreductase, phosphate acetyltransferase, and acetate kinase, were detected in the cell-free extract, indicating that the organisms produced ATP in the serine metabolism.


CONCLUSIONS
P. micros utilized serine-containing oligopeptides as exogenous metabolic substrates rather than serine itself, and degraded Ser-Ser-Ser and Ser-Tyr to formate, pyruvate, acetate, and ammonia with ATP generation.
Uematsu
H
H
Oral Ecology in Health and Infection, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Hossain
M Z
MZ
Alam
T
T
Ikeda
T
T
Kuvatanasuchati
J
J
Hoshino
E
E
D000084:Acetate Kinase; D000085:Acetates / Q000378:metabolism; D000123:Acetyltransferases; D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000641:Ammonia / Q000378:metabolism; D005560:Formate Dehydrogenases; D005561:Formates / Q000378:metabolism; D006801:Humans; D012695:L-Serine Dehydratase / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism*; D010462:Peptostreptococcus / Q000201:enzymology / Q000378:metabolism*; D010709:Phosphate Acetyltransferase; D050743:Pyruvate Synthase; D019289:Pyruvic Acid / Q000378:metabolism; D012694:Serine / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
D000085:Acetates; D005561:Formates; D009842:Oligopeptides; C030544:formic acid; D014443:Tyrosine; D012694:Serine; D000641:Ammonia; D019289:Pyruvic Acid; D000255:Adenosine Triphosphate; D005560:Formate Dehydrogenases; D050743:Pyruvate Synthase; D000123:Acetyltransferases; C022560:formate C-acetyltransferase; D010709:Phosphate Acetyltransferase; D000084:Acetate Kinase; D012695:L-Serine Dehydratase