Standard No.:	GB/T 47145-2026
English Name:	Recombinant protein reagents—Determination method of affinity
Chinese Name:	重组蛋白试剂 亲和力测定方法
Chinese Classification:	A40    Basic Subject in general
Professional Classification:	GB    National Standard
Source Content Issued by:	SAMR, SAC
Issued on:	2026-01-28
Implemented on:	2026-5-1
Status:	to be valid
Target Language:	English
File Format:	PDF
Word Count:	7000 words
Translation Price(USD):	210.0
Delivery:	via email in 1~3 business day

GB/T 47145-2026 Recombinant protein reagents—Determination method of affinity English, Anglais, Englisch, Inglés, えいご This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered. ICS 13.220.10 CCS H 57 National Standard of the People's Republic of China ‌GB/T 47145-2026 Recombinant protein reagents - Determination method of affinity 重组蛋白试剂 亲和力测定方法 Issue date: 2026-01-28 Implementation date: 2027-02-01 Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China the Standardization Administration of the People's Republic of China Contents Foreword 1 Scope 2 Normative References 3 Terms and Definitions 4 General Requirements 5 Principle 6 Reagents and Materials 7 Instruments and Equipment Recombinant Protein Reagents - Method for Affinity Determination 1 Scope This document describes the enzyme-linked immunosorbent assay method for determining the affinity of recombinant protein reagents. This document applies to the affinity determination of recombinant protein reagents such as cytokines, antibodies, and antigens. 2 Normative References The following documents contain provisions which, through normative reference in this text, constitute essential provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies. GB/T 6682 Water for analytical laboratory use - Specification and test methods GB 19489 Laboratories - General requirements for biosafety GB/T 40265 General testing rules for enzyme immunoassay antibodies 3 Terms, Definitions, and Abbreviations 3.1 Terms and Definitions For the purposes of this document, the following terms and definitions apply. 3.1.1 recombinant protein reagent A reagent prepared by purifying a protein expressed in a host expression system using technologies such as recombinant DNA. NOTE: Recombinant protein reagents, such as cytokines, antibodies, and antigens, are widely used for scientific research, diagnostics, or industrial purposes. Host expression systems include E. coli, yeast, insect cells, mammalian cells, or other cells. 3.1.2 affinity The strength of the interaction at a single binding site between a recombinant protein and its target under specified conditions. NOTE: Affinity is typically represented by the equilibrium dissociation constant (KDKD​), expressed in moles per liter (mol/L). 3.1.3 target A molecule that can be specifically recognized and bound by a recombinant protein under specified conditions. 3.2 Abbreviations The following abbreviations apply to this document. BSA: bovine serum albumin DNA: deoxyribonucleic acid ELISA: enzyme linked immunosorbent assay KDKD​: equilibrium dissociation constant OPD: o-phenylenediamine dihydrochloride PBS: phosphate buffered saline RP-HPLC: reversed-phase high-performance liquid chromatography SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis SPR: surface plasmon resonance TMB: 3,3',5,5'-tetramethylbenzidine 4 General Requirements 4.1 Unless otherwise specified, the reagents used in the test shall be of analytical grade or higher, and water shall comply with the provisions of GB/T 6682. 4.2 Reagents shall be stored and prepared according to the instructions. Before determination, the quality of the reagents shall be verified according to the reagent instructions or product quality reports to avoid test result deviations caused by changes in reagent performance. 4.3 Standard samples/reference materials or samples with documented values from literature shall be used as positive samples. Negative controls (proteins with no binding activity) shall be included in the test. 4.4 The handling of protein-containing samples and waste liquid shall comply with the provisions of GB 19489. 5 Principle The enzyme-linked immunosorbent assay method involves immobilizing the target on a solid-phase carrier surface, allowing it to bind with the test sample in solution to form an immune complex, and detecting it with an enzyme-labeled antibody. By measuring the absorbance values under equilibrium binding with different concentrations of the sample, a binding curve is plotted. The equilibrium dissociation constant (KDKD​) is calculated using nonlinear regression fitting to represent the affinity strength. 6 Reagents and Materials 6.1 Target Select the target for the test sample according to the application requirements. The target shall undergo physicochemical analysis (SDS-PAGE or RP-HPLC) and activity verification (ELISA or SPR) to ensure its purity and binding activity. 6.2 Coating Buffer Select an appropriate coating buffer based on the characteristics of the target to be coated. NOTE: Coating buffer example: 0.05 mol/L carbonate buffer solution at pH 9.6. 6.3 Diluent Select PBS at an appropriate pH or other equivalent buffer solution based on the characteristics of the test sample. A small amount of protein and a small amount of surfactant may be added to protect the activity of the target in the test sample and reduce background interference. NOTE: Protein example: 0.01 g/mL BSA; Surfactant example: Tween-20 at a volume fraction of 0.05%. 6.4 Washing Buffer Select PBS or other equivalent buffer solution containing an appropriate amount of surfactant. NOTE: Surfactant example: Tween-20 at a volume fraction of 0.05%. 6.5 Blocking Buffer Select PBS or other equivalent buffer solution containing a relatively high concentration of protein.