1. The method of conjugation of polysialic acid (PSA) or modified PSA (mPSA) with an oxidized carbohydrate portion of a glycoprotein other than a blood coagulation protein containing a carbohydrate group, comprising contacting the oxidized carbohydrate portion with a PSA or mPSA under conditions that allow conjugation, where the specified PSA or mPSA contain a hydrazide group and a hydrazone bond forms between the oxidized carbohydrate moiety and the hydrazide group on the PSA or mPSA. 2. The method of claim 1, wherein the PSA or mPSA is colominic acid or a modified colominic acid. The method according to claim 1 or 2, where the PSA or mPSA contains 2-500 units of sialic acid. The method of claim 1 or 2, wherein the glycoprotein is selected from cytokines such as interleukins, alpha, beta and gamma interferons, colony stimulating factors, including granulocyte colony stimulating factors, fibroblast growth factors, platelet growth factors, protein phospholipase activating (PUP) , insulin, plant proteins such as lectins and ricins, tumor necrosis factors and related allelic forms, soluble forms of tumor necrosis factor receptors, interleukin receptors and soluble forms of interleukin receptors, growth hormones, tissue growth factors, transforming growth factors such as TGFα or TGFβ, and epidermal growth factors, hormones, somatomedins, pigment hormones, hypothalamic releasing factors, antidiuretic hormones, prolactin, chorionic gonadotropin, follicle-stimulating hormone, thyroid stimulating hormone plasminogen and immunoglobulins such as IgG, IgE, IgM, IgA and IgD, monoclonal antibodies, erythro1. Способ конъюгации полисиаловой кислоты (PSA) или модифицированной PSA (mPSA) с окисленной углеводной частью гликопротеина, отличного от белка свертывания крови, содержащего углеводную группу, включающий контактирование окисленной углеводной части с PSA или mPSA в условиях, которые обеспечивают конъюгацию,где указанная PSA или mPSA содержат гидразидную группу и между окисленн
