Synthesis of chlorophyll-amino acid conjugates as models for modification of proteins with chromo/fluorophores.
A chlorophyll-a derivative bonded directly with epoxide at the peripheral position of the chlorin π-system was reacted with N-urethane and C-ester protected amino acids bearing an alcoholic or phenolic hydroxy group as well as a carboxy group at the residue to give chlorophyll-amino acid conjugates. The carboxy residues of N,C-protected aspartic and glutamic acids were esterified with the epoxide in high yields. The synthetic conjugates in dichloromethane had absorption bands throughout the visible region including intense red-side Qy and blue-side Soret bands. By their excitation at the visible bands, strong and efficient fluorescence emission was observed up to the near-infrared region. The chromo/fluorophores are promising for preparation of functional peptides and modification of proteins.
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan. Electronic address: tamiaki@fc.ritsumei.ac.jp.
Hitoshi
H
Tamiaki
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
Yasuaki
Y
Isoda
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
Takuya
T
Tanaka
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
Shinnosuke
S
Machida
D000596:Amino Acids / Q000737:chemistry*; D002384:Catalysis; D002734:Chlorophyll / Q000031:analogs & derivatives / Q000737:chemistry*; D000077194:Chlorophyll A; D004852:Epoxy Compounds / Q000737:chemistry; D004951:Esterification; D008958:Models, Molecular; D011166:Porphyrins / Q000737:chemistry; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D013055:Spectrophotometry, Infrared
D000596:Amino Acids; D004852:Epoxy Compounds; D011166:Porphyrins; D011506:Proteins; D002734:Chlorophyll; C040298:pyropheophorbide a; C006969:chlorin; D000077194:Chlorophyll A
Fluorescence emission data; Labeling; Pigment; Pyropheophorbide; Visible absorption spectra