The present application provides use of a CCDC157 gene and mutant genes thereof as molecular markers in diagnosis of male infertility diseases. Experiments have shown that the CCDC157-MIF515 mutant gene/protein causes male infertility, spermatogenesis disorder, sperm dysfunction, reduced sperm count, reduced sperm motility, abnormal sperm morphology, abnormal sperm head, etc. The CCDC157-MIF515 mutant gene/protein of the present application can be used as target genes for diagnosing male infertility. Meanwhile, the expression level of the CCDC157 of CCDC157 gene/protein is significantly reduced in NOA patients and SCOS patients, and the male infertility can be prevented and/or treated by increasing the activity and/or expression of the CCDC157 protein.

The technology described herein is directed to methods for obtaining partial sequence information from a target protein. Also described herein are systems, devices, and kits for obtaining partial sequence information from a target protein.

The present invention is directed to methods for detecting a plasma cell dyscrasia like myeloma or MGUS, methods for determining whether a plasma cell dyscrasiais stable or progressive, methods for determining a risk for disease relapse, and methods for determining a response by a subject having a plasma cell dyscrasia to a therapy.

The present invention relates to protein sequencing, more particularly the invention discloses improved aminopeptidases for single molecule protein sequencing and/or amino acid identification. Said aminopeptidases can enzymatically cleave off N-terminal amino acids and are highly suitable in a kinetics-based peptide sequencing approach. Based on the kinetics of the cleaving reaction or of the engagement between said aminopeptidases and peptide to be sequenced, information on the identity of the cleaved amino acids is provided.

Provided herein are methods of characterising a target polypeptide as it moves with respect to a nanopore. Also provided are related kits, systems and apparatuses for carrying out such methods.

The present invention provides a nanopore single-molecule protein sequencer, which mainly includes a nanopore array chip system, an ultra-low current detection system and a data processing and construction system; the chip mainly includes a chip of peptide charge screening, a chip of amino acid sequence reading based on a series of specific nanopores and the like, the design principle of which is as follows: a series of biological nanopores with amino acid targeted identification are designed according to properties such as hydrophilicity and hydrophobicity, polarity, and chargeability of amino acids, and characteristic ion flow signals of amino acids forming a protein to be detected in nanopore are obtained one by one; characteristic information of a protein sequence in each of the nanopores is acquired by an arrayed ultra-low current measurement system; a standard model peptide sequence information base is used for identifying, correcting, integrating and reading amino acid sequences.

The present invention relates to the field of biochemistry, more particularly to proteomics, more particularly to protein sequencing, even more particularly to single molecule peptide sequencing. The invention discloses means and methods for single molecule protein sequencing and/or amino acid identification using cleavage inducing agent. Said cleavage inducing agents which are not specific for one particular amino acid, cleave polypeptides step by step from the N-terminus onwards and provide information on the identity of the cleaved amino acids based on the kinetics of said reaction.

Aspects of the disclosure provide methods of identifying and sequencing proteins, polypeptides, and amino acids, and compositions useful for the same. In some aspects, the disclosure provides amino acid recognition molecule compositions, such as amino acid binding proteins comprising different labels, and methods of polypeptide sequencing using such compositions.

Disclosed is a method for evaluating in vivo protein nutrition based on an LC-MS-MS technique, including the following steps: (1) collecting contents from different intestinal segments, and extracting and isolating protein ingredients; (2) determining the concentration of proteins; (3) treating before carrying out mass spectrometry: including digestion and desalting of a whole protein solution; (4) LC-MS-MS analysis; (5) database searching; and (6) data processing. Proteomic technology is used to identify proteins in the contents of different intestinal segments and digestive products thereof, and the source of the proteins in the contents of different intestinal segments and the contents thereof can be determined therefrom. Through bioinformatic analysis, the function of differential proteins in the body can be further understood, where the gene expression of enzymes related to protein digestion and metabolism may be different, thereby providing a scientific basis for further scientific evaluation of protein digestion and utilization.

Aspects of the application relate to methods and systems for obtaining information regarding multiple amino acids in a polypeptide based on binding interactions between the polypeptide and one or more amino acid recognizers. Kinetic signature information may be obtained from a series of signal pulses indicative of a series of binding events between one or more amino acid recognizers and an amino acid of a polypeptide (e.g., a terminal amino acid, an internal amino acid). The kinetic signature information (e.g., pulse duration, interpulse duration, recognition segment (RS) duration, intersegment duration) may be used to determine one or more chemical characteristics (e.g., identity, modification) of multiple amino acids of the polypeptide.