Compositions and methods for analyzing disulfide bonds are provided. An exemplary method includes preparing peptide standards having no disulfide bonds, scrambled disulfide bond peptide standards, and native disulfide bond peptide standards according to the sequence of the region of the protein drug product that includes the disulfide bond, digesting a sample of protein drug product into peptides, separating the protein drug product peptides, analyzing the protein drug product peptides and the peptide standards, identifying scrambled and native disulfide bond peptides by retention time, and quantifying the level of scrambled disulfide bond peptides.

Examination of a test sample to determine the presence or quantity of succination of proteins is described. Examination can be via protein hydrolysis in total succination determination or via enzymatic digestion of isolated proteins and determination of the presence or quantity of modified peptides. The methods can be utilized for determination of excessive succination of lymph system proteins, which can be utilized in prevention or early detection of lymphopenia. Methods can be utilized for test samples of subjects under treatment with dimethyl fumarate suffering from multiple sclerosis. Methods can be utilized as a determination that treatment of the subject with DMF should be slowed or stopped.

A method for diagnosing the risk of glaucoma development, which can diagnose the risk of glaucoma development at the pre-disease stage, and to provide a new method to diagnose disease progression in the end-stage glaucoma. The method can include, for example, a diagnosing method for the risk of an ocular disease development or for the disease progression of an end-stage ocular disease by molecular profile analysis of the ocular anterior tissue microenvironment, comprising a step of measuring the concentration level of a metabolite appearing in the collected aqueous humor specimens by mass spectrometry (MS).

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 present disclosure relates to a composition for screening an intestinal environment-improving material and a screening method using the composition, and according to the composition and the method of the present disclosure, it is possible to provide an effective analysis method for screening a microbiota-improving candidate material in a personalized manner by providing a method for verifying personalized probiotics, prebiotics, foods, health functional foods and drugs under in vitro conditions based on microbiota and microbiota metabolites.

The present invention provides a method of measuring the quality of therapeutic cells through real-time glutathione monitoring.

The present invention relates to compositions and methods for determining the absolute configuration of D/L-cysteine and/or the enantiomeric composition of cysteine and/or the concentration of total cysteine in a sample. Uses of the composition and method are also described.

An in vitro method for diagnosing Alzheimer's disease (AD) includes determining the content of mercaptoalbumin (HMA) in a sample of cerebrospinal fluid (CSF), and comparing the content determined with the content of HMA in CSF in healthy subjects. If the HMA content is less than that of the healthy subjects, it is indicative of AD.

The present invention relates to compositions and methods for determining the absolute configuration of D/L-cysteine and/or the enantiomeric composition of cysteine and/or the concentration of total cysteine in a sample. Uses of the composition and method are also described.

The present disclosure relates to a novel compound or a salt thereof, a composition for detecting cysteine, a fluorescent probe, and a composition for diagnosing cancer, which contain the same, a method for detecting cysteine, a method for providing information for diagnosing cancer, and a method for producing the novel compound. According to the present disclosure, there may be provided a method of synthesizing and purifying a fluorescent probe for cysteine detection and applying the same to diagnose cervical cancer by detecting cysteine in human urine.