How Are Proteins Categorized? Proteins are categorized into groups called “protein families” based on shared evolutionary origins and similar characteristics. Families: Superfamilies Proteins in superfamilies are more distantly related to one another.Example: myoglobin and hemoglobin to neuroglobin Proteins classified by their shape are either globular or fibrous. Globular Proteins Globular proteins (aka spheroproteins) are spherically shaped. Examples: hemoglobin, immunoglobulinsSoluble in: water, acids, bases Fibrous proteins Fibrous proteins (aka scleroproteins) are elongated and strandlike, like wires. Examples: keratin, collagen, elastinSoluble in: strong acids and alkalisInsoluble in: water, weak acids, weak bases Proteins classified by composition are either simple or conjugated. Simple Proteins Simple proteins contain only amino acids. Conjugated Proteins Simple proteins contain only amino acids.Conjugated proteins contain both a protein and a non-protein component.