Protein Crystals

Protein crystals represent a crystalline form of protein. Artificially, P. c. were obtained by Hofmeister from egg albumin, by Giirber and Gruzewska from animal serum albumin, and by Magnus-Levy, Grutterink, and de Graafi from the protein body of Bence-Jones, which appears in the human body under certain pathological conditions. P. c. can have various crystalline forms and sizes. A common property of them is the ability to shrink from alcohol and resume their original appearance upon washing it out, as well as to be well stained by aniline 1S9 dyes; many P. c. possess double refraction. In nature, P. c. are distributed in the cells of many plants, having the significance of reserve inclusions, where they are most often found in seeds as inclusions of aleurone grains (see Aleuronate) or lie freely in the protoplasm, more rarely in the cell nucleus or chromatophore.

Protein crystals in myeloma, stained with methylene blue (observation by V. D. Vul'f).

In animals and humans, P. c. are physiologically present in the seminal and interstitial cells of the testes, and sometimes in the bone marrow. Under pathological conditions in humans, P. c. can be observed in the form of crystalline amyloid, Charcot-Leyden crystals, crystalline inclusions in large cells in Gaucher's disease; they are also sometimes found in the kidney tubules in albuminuria and in the tissue of some tumors [chloroma, myeloma (see figure)], forming in the latter cases from the protein body of Bence-Jones.