Provided herein are methods for detecting and quantifying succinate in a sample. Also provided are methods for detecting and quantifying 2-oxoglutarate oxygenase enzyme and/or 2-oxoglutarate oxygenase activity in a sample and methods for screening for modulators of 2-oxoglutarate oxygenase activity.

Provided in the present disclosure is a method for sequencing a double-stranded target polynucleotide. The method can keep ATP at a relatively constant concentration during sequencing, so that the sequencing rate can be better kept stable and unchanged. Further provided in the present disclosure is a kit for sequencing a double-stranded target polynucleotide, the kit including a transmembrane pore in the membrane, a helicase, an ATP-generating enzyme and an ATP-generating substrate.

The present invention relates to a kit comprising a DNA-dependant DNA polymerase and at least one natural deoxynucleoside and to a kit comprising a DNA-dependent DNA polymerase and a detection system comprising a DNA template molecule, a DNA primer molecule, and a fluorescent moiety capable of being displaced from, or bound to, dsDNA synthesized by said DNA-dependent polymerase. It further relates to A method for measuring deoxynucleoside kinase activity in a sample characterized by; (i) contacting the sample, in a container, with a reaction mix comprising a DNA-dependent DNA polymerase, at least one deoxynucleoside and a detection system comprising a DNA template molecule, a DNA primer molecule, and a fluorescent moiety capable of being incorporated in, displaced from, or bound to dsDNA synthesized by said DNA dependent polymerase; (ii) incubating said container; (iii) measuring the signal from the fluorescent moiety; and correlating the signal from the fluorescent moiety to the deoxynucleoside kinase activity in the sample.

The invention provides a method for determining the prognosis of an individual having cancer and being considered for treatment with, or currently being treated with, one or more immune checkpoint inhibitors, the method comprising or consisting of the steps of: a) providing a sample obtained from the individual prior to treatment with one or more immune checkpoint inhibitors; b) measuring the activity and/or concentration of thymidine kinase (TK) in the sample; c) providing a sample obtained from the individual 1-4 weeks after first treatment with the one or more immune checkpoint inhibitors; and d) measuring the activity and/or concentration of thymidine kinase (TK) in the sample provided in step (c); wherein the activity and/or concentration of thymidine kinase (TK) measured in steps (b) and (d) is indicative of the prognosis of the individual if further treated with one or more immune checkpoint inhibitors.