TERRAPUB Geochemical Journal

Geochemical Journal, Vol. 38 (No. 2), pp. 153-161, 2004

Distribution of amino acid and its stereochemistry related with biological activities in Rikubetsu, Hokkaido, Japan

Yoshinori Takano,1,2 Junya Kudo,2 Takeo Kaneko,2 Kensei Kobayashi,2,3* Yukishige Kawasaki4 and Yoji Ishikawa5

1Institute for Marine Resources and Environment, National Institute for Advanced Industrial Science and Technology (AIST), AIST Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan
2Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Hodogaya-ku, Yokohama 240-8501, Japan
3Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara 229-8510, Japan
4Mitsubishi Kagaku Institute of Life Science, 11 Minamiohya, Machida, Tokyo 194-8511, Japan
5Bio-Environmental Engineering Department, Technical Research Institute, Obayashi Corporation, 4-640 Shimokiyoto, Kiyose, Tokyo 204-8558, Japan

(Received November 18, 2002; Accepted September 19, 2003)

Abstract: Core samples of sediments at depths of 0-300 cm at Rikubetsu, Hokkaido, Japan were analyzed for total organic carbon (TOC) concentration, total hydrolyzed amino acids (THAA) and density of viable microorganisms. TOC, THAA and density of viable microorganisms were greatest at the surface and decreased with the depth: THAA showed 62 μmol/g at a depth of 0-5 cm. The correlation coefficients (r) for TOC and THAA versus cell density were 0.97 and 0.98, respectively. The alteration of dicarboxylic amino acids, aspartic acid and glutamic acid, to β-alanine and γ-aminobutyric acid respectively, via specific decarboxylation due to diagenesis were observed. Rate constant of aspartic acid racemization, kASP was determined to be 3.8 × 10−5 at 4,420 yrBP and 2.6 × 10−5 at 9,290 yrBP. Some anomalies in vertical distribution of THAA and cell density in the core sediment may indicate the presence of the past warmer period called “Hypsithermal” in Rikubetsu, Hokkaido, Japan.
Keywords: amino acid, stereochemistry, biological activity, vertical distribution, terrestrial sediment

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