Experiment Station Record, Volume 90, January-June, 1944 Page: 439

                                
1944]       AGRICULTURAL AND BIOLOGICAL CHEMISTRY                  439
scribed, consists of units of galacturonic acid, glucose, and some unidentified
sugar. A nitrogenous compound, apparently other than protein, is associated
with the polysaccharide.
The polysaccharide gives a positive skin reaction in sensitive individuals.
However, the polysaccharide obtained by regeneration from the acetyl derivative
no longer produces this skin reaction. Both the original polysaccharide and
that obtained from the acetylated derivative give positive precipitative
reactions.
Adrenocorticotropic hormone, C. H. LI, H. M. EVANS, and M. E. SIMPSON.
(Univ. Calif.). (Jour. Biol. Chem., 149 (1943), No. 2, pp. 413-142l illus. 3).The
authors extracted sheep pituitary glands with aqueous acetone acidified with
hydrochloric acid and obtained a precipitate by adding a large proportion of
chilled acetone to the cold extract and washings. The dry precipitate amounted
to 3 gm. from 2 kg. of the glands. This was further extracted with 0.1 M disodium
hydrogen phosphate, and the active material was all precipitable by halfsaturation
with ammonium sulfate. Further fractionation, including ammonia
treatment, ammonium sulfate fractionation, heat treatment, and sodium chloride
precipitation, was used in obtaining the hormone in pure form. Sedimentation
and solubility experiments indicated that it is a single substance. Biological
tests indicated that the hormone was freed from the other anterior hypophyseal
hormones. The molecular weight of the adrenocorticotropic hormone
was found to be approximately 20,000 and the isoelectric point about 4.7. The
hormone was very stable at 100 [C.] in buffer of pH 7.5 and in 0.1 M HCl solutions,
but not in 0.1 M NaOH. Its adrenocorticotropic activity was destroyed by
trichloroacetic acid and by tryptic digestion, but it had a marked stability to
peptic digestion (unimpaired when 37 percent digested).
Preparation and properties of pituitary adrenotropic hormone, G.
SAYERS, A. WHITE, and C. N.H. LONG (Jour. Biot. Chem., 149 (1943), No. 2, pp.
425-436, illus. 3).-A "crude prolactin" was prepared from hog pituitary glands,
which yielded 5 gm. per kilogram of this material. This first intermediate is
dissolved in 50 cc. of water at pH 9.0 with the aid of 2 N NaOH and the pH
lowered to 8.0 by the careful addition of 0.1 N HC1. The precipitate is discarded.
The supernatant solution is diluted with water to a volume of 235 cc.
and precipitates appearing at pH 6.6 and 5.4 are discarded. To the supernatant
(at pH 5.4) are added 17 cc. of saturated (NH4)2S04. A small precipitate which
forms overnight in the ice box is discarded. Four volumes of acetone are added
to the supernatant and the mixture is chilled. The precipitate (yield, 1.9 gm.)
is dissolved in 133 cc. of water with the aid of 0.1 N NaOH and the solution mixed
with one-half its volume of concentrated NH40H. The solution is allowed to
stand for 7 hr., and 1,800 cc. of acetone added. The precipitate (yield, 1.5 gm.)
is dissolved in 75 cc. of water and dialyzed against repeated changes of distilled
water until free of inorganic salt. Any precipitate which forms during dialysis
is discarded. The pH of the solution is carefully adjusted with 0.1 N HC1 to 5.4
and centrifuged free of precipitate. Lowering the pH of the supernatant to 4.7
precipitates adrenotropic hormone. This is washed three times with acetone
at the centrifuge and dried in vacuo over concentrated sulfuric acid. Yield, 400
mg. Some adrenotropic activity may be recovered from the supernatant of the
precipitate at pH 4.7 by the addition of acetone to a concentration of 40 percent.
Yield, 350 mg. Further purification to remove traces of remaining pressor substances
is also described.
The hormone preparation behaves as a single component in the Tiselius apparatus
and in the ultracentrifuge. The isoelectric point of adrenotropic hormone,
as determined by electrophoresis, is between pH 4.7 and 4.8. The sedi