Is there a particular molecular weight range you're looking for? This can be accomplished with dialysis and there are a range of pore sizes (ex: 10 kDa) that allow you to retain only larger proteins. Size-exclusion chromatography using Sepharose or similar columns will also suffice as the largest proteins will elute first.

Dear Vincent Schmitz,

Thank you for your answer.

Actually I do not have a particular molecular weight. I just want to extract the whole proteins contents of human serum.

Various methods are available, but most conventionally performed are salting out and serum electrophoresis. For whole serum exploration I will recommend eletrophoresis. If you want to study protein with defined molecular size then dialysis, size exclusion chromatography are available. Specific protein, then affinity chromatography are routinely done.

Dear Pranita Kamble Waghmare,

Thank you so much for your answer. It is really helpful.

Fresh serum should be separated by HPLC-Surf-SEC method (please see file; SEC column 300A silica).

By the way, serum of 52y female (healthy) has following major proteins (my unpublished observation; for child serum, please see file, JMBT Alopecia); i.e.,

Human serum albumin at 421.3, IgG (estimated) at 108.0, Ribonucleoside-diphosphate reductase subunit beta (Mycoplasma pneumoniae) at 22.1, Peroxisome proliferator-activated receptor gamma coactivator-related protein 1/PRC/PGC-1-related coactivator at 19.5, Non-structural protein NS2 (Bluetongue virus/BTV) at 18.4, Sphingosine-1-phosphate phosphatase 2 (membrane protein) at 17.7, Indolethylamine N-methyltransferase/Amine N-methyltransferase/Aromatic alkylamine N-methyltransferase at 17.1, Connectin/Titin (adult marker) at 16.6, Phenazine biosynthesis protein phzB1 (Pseudomonas aeruginosa) at 15.4, Lysosomal-trafficking regulator/Beige homolog (blood protein) at 14.5, Hemoglobin A (not from erythrocyte) at 13.4, Phosphatidylinositol 3,4,5-triphosphate-dependent Rac exchanger 1 protein/P-Rex1 (blood protein) at 12.5, Nucleoplasmin-3 at 11.6, F-box only protein 38/Modulator of KLF7 activity homolog at 10.9 μg/mg serum protein, respectively.