Work

Precipitation of Lysozyme with Thyroxine or Thyroglobulin

Year: 1965

Type: article

Abstract: Lysozymel from egg white or rat kidney is inhibited by Lthyroxine, or by L-triiodothyronine, in a system in which the enzyme and inhibitor are present in solution at pH 7.6 (2, 3).Kinetic studies showed that 1 molecule of thyroxine interacted with 1 molecule of enzyme, but the soluble complex proved to be unstable (2).This work has been confirmed in another laboratory.2The mode of inhibition of enzymatic activity, either by thyroxine or by triiodothyronine, was noncompetitive.Interest in the interaction of lysozyme and thyroxine in vitro stemmed from findings in tivo that the enzymatic activity in the rat kidney was markedly inhibited in a state approaching thyrotoxicity (4).Although recent work (5) suggests that combination of thyroxine and lysozyme in the rat kidney may not be of physiological importance, the nature of the interaction of the enzyme and the hormone in vitro is interesting from the point of view of the reactivity of thyroxine and of the kinds of structures to which the hormone binds.Surprisingly, an increase in the concentration of the hormone in the soluble system by 3 to 10 times resulted in the precipitation of a complex between the hormone and the enzyme.The nature of this complex and a similar one in which thyroglobulin can replace thyroxine is the subject of the present communication.EXPERIMENTAL PROCEDURE ReactantsCrystalline egg white lysozyme was obtained from the Biochemical Department of The Armour Laboratories and was usually over 85 y0 homogeneous in the Tiselius electrophoresis apparatus (ascending boundary).Some experiments were performed with egg white lysozyme obtained from the Worthington Biochemical Corporation.L-Thyroxine was obtained from Glaxo Laboratories, Ltd.This preparation produced a single zone on paper electrophoresis.Hog thyroglobulin was obtained from Pentex, Inc.This preparation contained 0.9% iodine and was about 91 y. homogeneous in the Tiselius electrophoresis apparatus (ascending boundary).Crystalline beef pancreatic

Source: Journal of Biological Chemistry

DOI: 10.1016/s0021-9258(17)45227-6

Authors: Gerald Litwack, Mary Lou Sears

Institution: Temple University

Language: English

Topic: Thyroid Disorders and Treatments

Subfield: Endocrinology, Diabetes and Metabolism

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,430