Ezi proteni zibaziinqwelo zokuthutha ezinye izakha-mzimba ezincinane kakhulu ngegazi, zibengantibodies| amajoni omzimba (nabizwa ngokuba zii-immunoglobulins), zijongana neziganeko zokwenzeka kwamahlwili, kunye namagatya eeproteni. I-Plasma ayinayo iproteni eyenza amahlwili yiyo le nto kuthiwa xa ibizwa yi-serum kwaye ayinakubalihlwili. Zi-3 iilitha zeplasma ezinokufumaneka kubantu abadala. IPlasma ingamanzi, singathi amanzi akuyo amalunga nama-(90%). Kananjalo iplasma inobunzima begazi obunokude bubengama-55%.