Glandular mucoprotein

When 1.5 volumes acetone is added to the trichloroacetic acid filtrate of the gastric juice, an abundant flocculent precipitate forms, which contains all the components of dissolved mucin with the exception of soluble mucus. If this precipitate is taken up in dilute alkali and then acidified with dilute HCl down to pH 3.5, a fine flocculent precipitate forms, which we named dissolved mucoprotein (G27, G36). It was later renamed glandular mucoprotein (G9, G38) because of its close relationship to the fundic glands of the stomach. This material contained much protein its nitrogen content was 12.61 0.44% and its tyrosine content 7.50 0.65% by the Folin-Giocalteu reaction. The reducing substance content was 6.38 1.48% before and 12.5% after hydrolysis (G9, G27, G36) (see Table 4). Werner (W9) determined the composition of this mucoprotein fraction and found that it contained 11.2% N by Kjeldahl, 8.8% hexosamine, 4.8% uronic acid, and 2.0% sialic acid. 

One aspect of the biological activity of the glandular mucoprotein fraction was its relationship to Castle s intrinsic factor (GIO, G37). A daily dose of 50-100 mg of this material, when given to pernicious anemia patients with small oral doses of vitamin Bis, brought about a striking hematopoietic response. This activity was due, as we now know, to the content of the proteolytic degradation product of intrinsic factor (G12, G14, G18, G20, S22). 

Chahactehistics of Glandular Mucoprotein AND MuCOPHOTEOSE IN GaSTRIC JuICE... 

When we processed dissolved mucoprotein in 1955 from gastric juice of various human subjects, and under conditions of variable stimulation, this material showed some variations in protein and hexose contents. Therefore, we stated at that time When we looked for explanation of these variations by elution of the paper electrophoretic strips, we found that the leading fast boundary corresponding to glandular mucoprotein contained much pepsin. This pepsin apparently has been inactivated... 

Relationship between Pepsin and Glandular Mucoprotein Concentration IN 33 Individuals Prior and During Stimulation of Gastric Secretion RY Histamine and Insulin... 

Specimens Pepsin (PUnb X lOVml) (means and ranges) Glandular mucoprotein (mg/lOOml) (means and ranges) Ratio pepsin to mucoprotein (means and ranges)... 

Since 1960 it has become evident (G18) that glandular mucoprotein fraction represents a complex of materials which include the following ... 

Ratio of Hexoses to Tyrosine in Glandular Mucoprotein and Mucopro-teose Fractions of Gastric Gollections from 15 Individuals... 

Hexosamine to Tyrosine Ratio in Mucoprotein H (= Mucoproteose) and Mucoprotein V (= Glandular Mucoprotein) Fractions of Dissolved Gastric Mucin Collected Under Similar Conditions from Heidenhain Pouches of 4 Docs... 

Glass, Boyd, Rubinstein, and Svigals Glandular mucoprotein from normal gastric juice 50-200 mg... 

According to Peressini et al., oral administration to infants of glandular mucoprotein" causes improved fat absorption (P4). Blood lipids increase after feeding this material. The marked effect upon the lipids is not identical with that of vitamin B12, nor is it due to the B12 absorption-promoting effect of this mucoprotein. The relationship of this factor to that of Balfour is not known. 

G9. Glass, G. B. J., The derivation and physiological significance of the glandular mucoprotein of human gastric juice The relation of its secretion to atrophic processes in the stomach. J. Natl. Cancer Inst. 13, 1013-1022 (1953). 

G37. Glass, G. B. J., Boyd, L. J., Rubinstein, M. A., and Svigals, C. S., Relationship of glandular mucoprotein from human gastric juice to Castle s intrinsic antianemic factor. Science 115, 101-108 (1952). 

The electrophoretic pattern of glandular mucoprotein was distinctly different from that of mucoproteose, since it displayed a single, slightly asymmetrical peak of fast negative mobility, ranging from — 8.5 X 10 to —7.2 X 10 in phosphate buffer over the pH range 6.0-7.3. 

Fig. 1. A The electrophoretic pattern of gastric juice from a healthy subject in 0.1 ionic strength veronal buffer at pH 8.6 and a protein concentration of 3.9. B The same after addition of glandular mucoprotein. C The same as A after addition of mucoproteose. From Mack et al. (Ml).

Fig. 24. Immunoelectrophoresis of human gastric juice. Immunoelectrophoietic patterns A, in vitro depepsinized normal gastric juice B, crystalline human pepsin C, crystalline human gastricsin D, human serum albumin E, glandular mucoprotein F, mucoproteose C, rapid vitamin Bj2 binder H, slow vitamin B 2 binder. Anti-gastric juice immune serum was used throughout. From Simons and Grasbedc (S9).

Norpoth et al. (N3) compared electrophoretic patterns oi mucoprotein and mucoproteose with those of various other fractions precipitated from the gastric juice. When gastric juice was precipitated by Martin s method (see G5) the gastroglobulin, which is similar to dissolved mucin, showed two peaks which had electrophoretic localization of the glandular mucoprotein and mucoproteose fractions, respectively. Collodion filtration of... 

For several years Glass and his colleagues (1952) have held the view that Castle s intrinsic factor was identical with or associated with the soluble glandular mucoprotein fraction of normal gastric juice. This muco-protein was believed to come from the cells at the neck of glands in the fundus (corpus) mucosa of the human stomach. During electrophoresis this substance moved towards the anode, and was the most acid protein in gastric juice. 

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