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A new method is described for the isolation of the subunits of porcine luteinizing hormone which have not been characterized before. By chromatography on SE-Sephadex C-25 in 8 M urea, the two subunits LHa and j3 were obtained in good yield and without apparent cross contamination. The physicochemical and immunological properties of these subunits were studied. Unlike the bovine or ovine LHj3 subunits described earlier, porcine LHB subunit does not contain lysine.Porcine LHoc subunit is electrophoretically heterogeneous and two components represented by two homogeneous electrophoretical zones were isolated and characterized. The amino acid composition of these components is very similar; they differ, however, slightly in peptide maps of their tryptic digests. Whole LHa subunit was submitted to specific cleavage at methionine residues by cyanogen bromide and a homogeneous peptide not containing homoserine was isolated. The latter represents most probably the C-terminal fragment of LHa subunit. Its partial amino-acid sequence and composition is : Gly-Asn-Ala-Arg-Val-Glu-(His, ,Lys,CM-Cys,-,,Asp ,Thr,,Ser,Glu,Tyr,)-Ser .The fragment contains 34O/, of sugar (by weight). I n view of the similarity in peptide maps and the unambiguous sequence described above, the primary structure of the different components of LHa subunit must be very similar. This paper described the properties of porcine luteinizing hormone and its subunits which have not been characterized before. A new method of preparation of the subunits based on ion-exchange chromatography in dissociating buffers is described. When submitted to starch-gel electrophoresis in 8 M urea, the material corresponding to the subunit LHP appears as homogeneous while the subunit LHol contains several electrophoretical components.Note. According to a proposal of Dr. J. G. Pierce and H. Papkoff (personal communication) the subunits of luteinizing hormone will be designated as LHa and LHB instead of LH CI and CII as previously described [3].Enzyme. Trypsin (EC 3.4.4.4).The possible reason for this heterogeneity was investigated by comparing the chemical properties and the peptide maps of the material corresponding to homogeneous electrophoretical components. The isolation of a peptide representing most probably the C-terminal portion of the subunit LHa is described and its partial amino acid sequence is presented. MATERIAL AND METHODS Preparation

A mathematical model of the deformation of the analyte zone in capillary zone electrophoresis (CZE) due to capillary coiling is presented and the influence of capillary coiling on the distribution of electric current density inside the capillary is described. The model gives a quantitative description of the potential contribution of capillary coiling to the total zone dispersion in CZE. The zone broadening caused by capillary coiling is calculated as the difference of migration distances of the particles migrating at the inner circumference of the capillary coil and those migrating at the outer circumference. This difference is shown to be directly.proportiona1 to the capillary diameter and to the number of capillary coils, i.e. indirectly proportional to the radius of the capillary coils into which the capillary of the given length is coiled. The contribution of capillary coiling to the total zone dispersion is compared with the contribution of the longitudinal diffusion of low and high molecular mass analytes and bioparticles. It is shown that, especially in the case of CZE separation of macromolecules and particles, capillary coiling can significantly decrease the separation efficiency. For that reason the small radius coiling of the capillary column in the CZE apparatuses should be avoided. Nonstandard abbreviations: BGE, background electrolyte; HETP, height equivalent of theoretical plate

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