Interaction of delta-chymotrypsin with proflavine

A 1:1 molar stoichiometry has been found for the noncovalent bonding of proflavine with δ-chymotrypsin. The dissociation constant at pH 7.6 is 0.025 mM which is similar to that found by Glazer for the reaction of proflavine with α-chymotrypsin. The difference spectrum produced by the proflavine–δ-chymotrypsin interaction has been studied as a function of pH. It would appear that a group with pK of approximately 6.5 is involved.

Radioimmunoassay of follicle-stimulating (FSH) and luteinizing (LH) hormones by chromatoelectrophoresis

Procedure for the radioimmunoassay of FSH and LH using chromatoelectrophoresis for the separation of antibody-bound and free labeled hormone is described. Diurnal variation in FSH and LH levels of normal men and women in follicular and luteal phases of the cycle is reported. The diurnal variation was not abolished in three women taking contraceptive medication and in two women in postmenopause. The diurnal variation of FSH and LH in plasma is compared with that of cortisol, dehydroepiandrosterone and testosterone. It is suggested that diurnal variation of FSH and LH may be independent of a normally functioning pituitary-gonadal axis; however, steroidal feed-back may have a regulatory effect on the magnitude of the diurnal variation. The plasma levels of FSH and LH in normal subjects during normal menstrual cycles as well as in patients with endocrinopathies obtained in our laboratory by radioimmunoassay are compared with those obtained by both radioimmunoassay and bioassay by other investigators.