Hisao Oka

A Nonempirical Method Using LC/MS for Determination of the Absolute Configuration of Constituent Amino Acids in a Peptide:  Combination of Marfey's Method with Mass Spectrometry and Its Practical Application

Kiyonaga Fujii, Yoshitomo Ikai, Hisao Oka et al. · Analytical Chemistry · 1997 · 457 citations

Peptide Science, Analytical Chemistry, Liquid Chromatography +18

A Nonempirical Method Using LC/MS for Determination of the Absolute Configuration of Constituent Amino Acids in a Peptide:  Elucidation of Limitations of Marfey's Method and of Its Separation Mechanism

Kiyonaga Fujii, Yoshitomo Ikai, Tsuyoshi Mayumi et al. · Analytical Chemistry · 1997 · 340 citations

Amino Acids, Peptide Science, Analytical Ultracentrifugation +23

Formation, characterization, and toxicity of the glutathione and cysteine conjugates of toxic heptapeptide microcystins

Fumio Kondo, Yoshitomo Ikai, Hisao Oka et al. · Chemical Research in Toxicology · 1992 · 202 citations

Analysis and purification of toxic peptides from cyanobacteria by reversed-phase high-performance liquid chromatography

Ken-ichi Harada, Kenji Matsuura, Makoto Suzuki et al. · Journal of Chromatography A · 1988 · 179 citations

Engineering, Biochemistry, Bioanalysis +10

Systematic search for suitable two-phase solvent systems for high-speed counter-current chromatography

Fumie Oka, Hisao Oka, Yoichiro Ito · Journal of Chromatography A · 1991 · 173 citations

High-speed Counter-current Chromatography, Chemical Engineering, Engineering +12