A 
globular protein is a 
protein that is globe-like, or rounded in shape, often soluble in 
aqueous solution. This distinguishes them from 
fibrous proteins[?], such as 
keratin, which may not be all that soluble. The term is old,  perhaps 19th century, predating the discovery of secondary structural motifs, and does not require the kinds of techniques used in modern structural biology. Something as simple as an 
ultracentrifuge can, via 
sedimentation coefficients, give useful information about a protein's globular nature.
Among the most known globular proteins is hemoglobin , a member of the globin protein family[?].
 
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