In accordance with some embodiments herein, methods of determining signatures of HMGB1 isoforms in a subject are provided. In some embodiments, antibodies that bind specifically to HMGB1 isoforms are provided. In some embodiments, immunoassay kits are provided.

Described herein is a method for assessing disulfide bond reduction potential of a protein of interest comprising the following steps: Providing a cell culture fluid sample comprising mammalian cells expressing a protein of interest at a concentration within the range of between 0.2 g/l to 10 g/l Filtering said cell culture fluid sample over at least one filter Displacing O.sub.2 in the filtered cell culture fluid sample Collecting at least one sample of the O.sub.2-displaced filtered cell culture fluid sample Separating the proteins in said at least one O.sub.2-displaced, filtered cell culture fluid sample according to their size under non-denaturing conditions Determining the disulfide bond reduction potential of the protein of interest.

The purpose of the present invention is to provide a method for detecting, in a selective and simple manner, an oxidized form of HD5 which is human α-defensin, that is, HD5 having intramolecular disulfide bonds that function beneficially in the human body.

[Solution] The present invention relates to: two kinds of novel monoclonal antibodies that contain amino acid sequences of SEQ ID NO: 1-6 or 7-12 as a CDR and that specifically bind to human α-defensin HD5 having intramolecular disulfide bonds; an immunological detection method using the antibodies; and a kit containing the antibodies.

The present invention generally pertains to methods of preventing disulfide scrambling in non-reducing liquid chromatography-mass spectrometry analysis of a protein of interest. In particular, the present invention pertains to the addition of cystamine to a non-reducing liquid chromatography-mass spectrometry analysis of an antibody to prevent disulfide scrambling.

The present invention generally pertains to methods of preventing disulfide scrambling in non-reducing liquid chromatography-mass spectrometry analysis of a protein of interest. In particular, the present invention pertains to the addition of maleimide to a non-reducing liquid chromatography-mass spectrometry analysis of a protein to prevent disulfide scrambling.

The present disclosure relates to a marker for diagnosing neurodegenerative diseases, and a use thereof, and, more particularly, to: a marker composition for diagnosing neurodegenerative diseases; a composition for diagnosing neurodegenerative diseases, containing a preparation for measuring the glutathionylation level of a FUS protein; a kit for diagnosing neurodegenerative diseases, containing the composition; and an information providing method for diagnosing neurodegenerative diseases by using same. The inventors have discovered that a glutathionylated FUS protein functions as a marker for diagnosing neurodegenerative diseases, and thus a composition for diagnosing neurodegenerative diseases, according to the present disclosure, is expected to contribute to early diagnosis of patients with neurodegenerative diseases.

In addition, the present disclosure identifies GSTO1 or GstO2, which is a factor inducing the deglutathionylation of a FUS protein, so as to ascertain effects of inhibiting brain cytoplasmic aggregation and neurocytotoxicity by using same, and thus is expected to be effectively used for preventing, treating or alleviating neurodegenerative diseases.

Methods for peptide and/or protein quantification by mass spectrometry using labeled peptides, wherein multiple labels lead to distinct fragments for the labeled peptides and their unlabeled variant, thus facilitating data analysis and enhancing the potential for quantification. Methods for selecting the label and label position are further given, as well as sets of labeled peptides resulting from or for use in the above-mentioned methods. The methods and substances are especially useful for data-independent or multiplexed parallel reaction monitoring proteomics applications involving peptide quantification.

Methods for peptide and/or protein quantification by mass spectrometry using labeled peptides, wherein multiple labels lead to distinct fragments for the labeled peptides and their unlabeled variant, thus facilitating data analysis and enhancing the potential for quantification. Methods for selecting the label and label position are further given, as well as sets of labeled peptides resulting from or for use in the above-mentioned methods. The methods and substances are especially useful for data-independent or multiplexed parallel reaction monitoring proteomics applications involving peptide quantification.

Methods for peptide and/or protein quantification by mass spectrometry using labeled peptides, wherein multiple labels lead to distinct fragments for the labeled peptides and their unlabeled variant, thus facilitating data analysis and enhancing the potential for quantification. Methods for selecting the label and label position are further given, as well as sets of labeled peptides resulting from or for use in the above-mentioned methods. The methods and substances are especially useful for data-independent or multiplexed parallel reaction monitoring proteomics applications involving peptide quantification.

Embodiments described herein relate to devices, and methods for quantifying thiol content in a sample containing a mixture of proteins or protein isoforms. The method includes conjugating a portion of the sample with free thiol detection binders, separating the contents in the portion of the sample into separated protein isoforms, detecting fluorescence signals associated with each separated protein isoform, and quantifying, based on the fluorescence signals, a relative amount of free thiol associated with each separated protein isoform. In some instances, the method includes quantifying the amount of each separated protein isoform based on absorbance signals associated with each separated protein isoform. In some instances, the fluorescence and/or absorbance signals associated with protein isoforms conjugated with detection binders can be compared with the corresponding signals associated with unconjugated protein isoforms. In some instances, the method further includes applying a reducing agent and quantifying total-thiol content in the sample.