Abstract:
Enzyme substrates each carrying in its molecule a group which is cleaved by the enzymatic reaction and another group which is cleaved by the enzymatic reaction and then forms a coumarin derivative by intramolecular lactonization. A method for assaying enzymatic activity which comprises effecting an enzymatic reaction with the use of the above substrate and then measuring the fluorescence of the coumarin derivative thus formed to thereby determine the enzymatic activity.
Abstract:
A solid phase for target nucleic acid detection which has a base sequence hybridizable in sequence with a specified polynucleotide sequence of a target nucleic acid and contains a set of probes with their spatial arrangement immobilized onto the solid phase through a linker portion so as to be enzymatically ligated during the hybridization; and a method of target nucleic acid detection which comprises hybridizing the solid phase with the target nucleic acid, ligating the probes by a ligase reaction, and detecting the product of ligation.
Abstract:
A fluorescent immunoassay characterized by labeling a sample with a fluorescent marker having a nucleic acid moiety stained with such a sufficient number of fluorochromes as to enable the measurement of fluorescent spots and a reactive group capable of binding specifically to the sample, immobilizing the sample thus labeled onto a solid phase, and then counting the fluorescent spots. The nucleic acid moiety of the fluorescent marker is a double- or single-stranded nucleic acid. Staining with the fluorochromes is effected with the use of intercalater type fluorochrome(s), mirror group type fluorochrome(s), and fluorochrome(s) covalently bonded to the nucleic acid.
Abstract:
A photocleavable cyclic oligonucleotide having a base sequence capable of hybridizing with a target DNA or RNA and a structure cyclized with a photocleavable linkage. The oligonucleotide is not decomposed by nucleases in the living body owing to its cyclic structure, so that it can be diffused to predetermined positions in the body by taking a sufficiently prolonged time. Further, the linkage is cleaved by irradiation with a suitable light after the lapse of a predetermined time, by which the cyclic oligonucleotide is converted into a linear one, thus acting as an antisense oligonucleotide.
Abstract:
A method and apparatus for determining enzyme activities by supplying a substrate solution and an enzyme solution to a reaction vessel to which a total reflection absorption prism is connected. An assay solution (40) comprising a mixture of an enzyme solution and a substrate solution is brought to a constant temperature in a reaction vessel (26) by a thermostat (23) and stirred by an agitator (21). An infrared ray (36) sent out of an infrared ray source (3) enters an interface between a total reflection absorption prism (28) in contact with the assay solution (40) and the solution (40) from the side of the prism (28), and is totally reflected thereupon. The spectrum of the totally reflected, outgoing transmitted infrared ray (37) is detected by an infrared ray detector (5), and the variation of the infrared ray absorption spectrum or absorbance is determined on the basis of what has been detected, whereby the enzyme reaction in the object solution (40) is assayed.
Abstract:
The polarization of fluorescent light or Raman scattering light which is emitted from a sample when light is applied to the sample is measured with high accuracy. Excitation light which is emitted from a pulse excitation light source (1) and is p-polarized by a polarizer (2) and a half-wave plate (3) is applied to a sample (7) and the p-polarization component intensity Ipp and s-polarization component intensity Ips of the emitted fluorescent light are measured by photodetectors (13 and 14). In the same way, s-polarized excitation light is applied to the sample (7) and the p-polarization component intensity Isp and s-polarization component intensity Iss of emitted fluorescent light are measured. The G-factor is obtained from those measured values by a following formula: G = [(Ipp.Isp)/(Ips.Iss)] . Polarization responsiveness correction is performed in accordance with the G-factor to obtain the polarization of the fluorescent light.
Abstract:
Detection probes enabling very convenient and highly accurate and sensitive detection of DNAs or RNAs having specific base sequences in specimens in the presence of the probes in excess of the target nucleic acid; and a detection method. When mixed with a specimen containing the target substance (DNA, RNA, etc.) having a polynucleotide having a specific base sequence, two types of fluorescent label detection probes hybridize, while being adjacent to each other, with the target nucleic acid. As a result, there arises a shift of the resonance energy between the two types of fluorescent dye molecules. When the resonance energy shift occurs in the hybrid thus formed, the fluorescence attenuation of the acceptor fluorescent dye molecule can be sufficiently delayed compared with the fluorescence attenuation of the directly excited acceptor by appropriately regulating (1) the number of bases between the two nucleotides to which the fluorescent dye moleculees have bonded; (2) the structure (double- or single-stranded) of the hybrid between the two nucleotides to which the fluorescent dye molecules have bonded; and (3), on the detection probes, the sites of the nucleotides into which the fluorescent dye molecules are to be introduced; and by (4) using a pair of detection probes with the appropriate selection of the fluorescent dye molecules. The detection method comprises using the above-mentioned detection probes and detecting the target substance by measuring changes in the fluorescence attenuation curve of the acceptor after the irradiation with pulse excitation rays, thus enabling highly accurate and sensitive detection of the target nucleic acid in the presence of the detection probes in excess of the target nucleic acid.
Abstract:
This invention relates to a pair of probes for the detection of a target nucleic acid, said pair of probes comprising (1) probe 1 having base sequence B1 complementary to A1 between two specific sequential base sequences A1 and A2 of the nucleic acid, wherein (a) the 5'-terminus of base sequence B1 is phosphorylated and (b) a first solid phase immobilizing part is bound to the 3'-terminus of base sequence B1, and (2) probe 2 having base sequence B2 complementary to A2 between base sequences A1 and A2, wherein (a) the 5'-terminus of base sequence B2 is bound to one end of a cleavage part and (b) a second solid phase immobilizing part is bound to the other part of the cleavage part. When the target nucleic acid is hybridized above the solid phase of the invention where said probes are immobilized on its surface, the probes on the solid phase occupy spatial positions beneficial to the formation of a hybrid and thus forms the hybrid efficiently. Therefore, probe 1 and probe 2 are efficiently ligated by ligase reaction. Furthermore, after the target nucleic acid is removed from the hybrid, only probe 2 ligated as described above will be able to exist on the solid phase through cleavage reaction of the cleavage part. Therefore, after the free probe 2 has been removed by washing, it will become possible to detect the presence of probe 2 on the solid phase ligated as described above, with high sensitivity and high recognition. This will enable detection of the presence of a target nucleic acid with higher sensitivity and higher recognition as compared to methods in the prior art.
Abstract:
The enzyme substrate according to this invention has within its molecule both a group to be cleaved by an enzyme reaction and a group that forms a strongly fluorescent coumarin derivative through intramolecular lactonization when cleaved by the enzyme reaction. Furthermore, the method for determining an enzyme activity according to this invention comprises conducting the enzyme reaction by the use of the enzyme substrate of the invention and determining the enzyme activity by means of the measurement of fluorescence of the coumarin derivative formed.