Hamamatsu-photonics K.k.

Laboratory of Molecular Biophotonics

Kiyohito Shimura

Kenichi Kasai

Hiroyuki Matsumoto

Sunao Hisada

Yukiko Ito

Hisayoshi Takamoto

Disclosed is an isolated polynucleotide encoding a modified Fab' antibody, which includes an Fd chain and an L chain with the Fd chain including a CH1 region and the L chain including a CL region, wherein the modified Fab' antibody further includes a cysteine for binding to a fluorescent dye, and the polynucleotide includes an Fd chain coding region and an L chain coding region linked therebetween in a manner that will allow expression of the modified Fab' antibody. Also disclosed are an expression vector containin the isolated polynucleotide, an isolated transformed host cell containing the expression vector, and a cell culture including the transformed host cell.

Isolated Polynucleotide encoding modified fab' antibody, expression vector, and transformed host cell

A method for quantitatively detecting an antigen which comprises (1) a first step of providing an Fab' antibody having a uniform isoelectric point, said antibody forming an immune complex with an antigen in an analytical sample and being modified by adding an amino acid sequence comprising a charged amino acid residue and by being labeled with a fluorescent dye, (2) a second step of mixing the Fab&#x2032; antibody having a uniform isoelectric point with the analytical sample containing the antigen to obtain a mixture comprising the immune complex, (3) a third step of separating the mixture by performing electrophoresis in a carrier, (4) a fourth step of irradiating an excitation light which excites the fluorescent dye to the mixture separated in the third step to cause fluorescence in the immune complex, and (5) a fifth step of detecting the fluorescence.

Method for quantitatively detecting antigen

Provided are isoelectric point(pI) markers for isoelectric focusing with fluorescence detection. The markers are fluorescence-labeled oligopeptides which comprise a fluorescence dye bonded chemically to the amino group of N-terminal amino acid of oligopeptide. The marker shows its unique and narrow pI band(peak) in electrophoresis or isoelectric focusing. The markers can be designed to have appropriate pI value, and cover wide range of pI (3&lt;pI&lt;11). Further, the markers have good storage stability. The markers can be preferably applied to the capillary isoelectric focusing with fluorescence detection due to their sharp and narrow band with strong emitted fluorescence.

Growing community of inventors

Kanagawa, Japan

Kiyohito Shimura