ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Large crystals of hen egg-white (HEW) lysozyme, both tetragonal and orthorhombic, have been studied with a goniometer and optical methods. As the crystals are particularly stable, some of their optical properties have been measured, mainly the refractive indices determined from reflectance measurements under a photometric microscope. Orthorhombic HEW lysozyme: crystals show the faces (010), (011) and (110). Refractive indices n[001] = ng = 1-562 to 1.547 (λ = 480-640 nm); n[100] = nm = l.560 to 1.544; n[010] = np = 1.550 to 1.532. Maximum birefringence 0.013 (λ) = 589 nm). Optic axial angle 2V =48 to 51°. Tetragonal HEW lysozyme: crystals formed by the association of a tetragonal {110} prism and a {101} tetragonal bipyramid. Refractive indices n[001] = nc and n[100] = no, with an aging phenomenon in these crystals, ne varying between 1-580 and 1.545, no between 1.575 and 1.538 (λ = 589 nm). Maximum birefringence 0.007. HEW lysozyme crystals are examples of good-quality protein crystals. Their refractive indices are surprisingly high for organic substances.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739474001550
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