LECTURE I. The general nature of Proteolytic Enzymes and of Proteids. | Introductory observations, | 1 | | Early history of gastric digestion, | 3 | | The proteolytic power of the pancreatic juice, | 7 | | The general nature of proteolytic enzymes, | 8 | | Origin of proteolytic enzymes, | 8 | | Preparation of pepsin, | 10 | | Reactions and composition of proteolytic enzymes, | 13 | | The proteid nature of enzymes, | 15 | | Conditions modifying the action of enzymes, | 17 | | The influence of temperature on proteolytic action, | 18 | | The influence of acids, alkalies, and other substances on the activity of enzymes, | 20 | | Action of chloroform on pepsin, | 21 | | Theories of enzyme action with special reference to catalysis, | 22 | | The general nature of Proteids, | 27 | | Classification of proteids, | 29 | | Chemical composition of some of the more prominent proteids occurring in nature, | 31 | | Chemical constitution of proteids, | 33 | | The presence of hemi- and anti-groups in all typical proteids, | 34 | | Cleavage of the albumin-molecule with dilute sulphuric acid, | 34 | | Hydration and cleavage of albumin by the action of superheated water, with formation of atmid-albumoses, etc., | 37 | | Action of powerful hydrolytic agents on proteid matter, | 39 | | Initial action of pepsin-acid on proteids, | 40 | | Scheme of the general line of proteolysis as it occurs in pepsin-digestion, with a view to the structure of the albumin-molecule, | 41 |
LECTURE II. Proteolysis by pepsin-hydrochloric acid, with a consideration of the general nature of proteoses and peptones. | Proteolysis by pepsin-acid, | 44 | | Formation of hydrochloric acid in the gastric glands, | 45 | | Liebermann’s theory regarding the formation of the acid of the gastric juice, | 46 | | Differences in the action of free and combined acid, | 47 | | Proteolysis in the presence of combined acid, | 49 | | The combining power of various forms of proteid matter with hydrochloric acid, | 51 | | Quantitative estimation of the affinity of the products of digestion for acid, | 53 | | Richet’s theory regarding the conjugate character of the acid of the gastric juice, | 54 | | Proteolysis in the presence of amido-acids, | 55 | | Necessity for knowing the amount of combined acid in the stomach-contents, | 57 | | Antiseptic action of the hydrochloric acid of the gastric juice, | 58 | | The maximum action of pepsin exerted only in the presence of free hydrochloric acid, | 59 | | Division of the products of pepsin-proteolysis into three main groups, | 60 | | Detection of the products of digestion, | 61 | | Separation of proteoses and peptones from a digestive mixture or from the stomach-contents, | 62 | | Some of the chemical properties of peptones, | 64 | | The so-called propeptone a mixture of proteoses, | 65 | | Pepsin-proteolysis synonymous with a series of progressive hydrolytic changes, | 66 | | Chemical composition of proteoses and peptones, | 67 | | Pepsin-proteolysis a true hydrolytic and cleavage process, | 71 | | SchÜtzenberger’s results on the formation of fibrin-peptone, | 72 | | Amphopeptones the final products of gastric digestion, but proteolysis never results in complete peptonization, | 73 | | Solution of a proteid by pepsin-acid not synonymous with peptonization, | 75 | | Influence of the removal of the products of digestion on the activity of the ferment, | 75 | | Lack of complete peptonization by pepsin-acid not due to accumulation of the products of digestion, | 76 | | The diffusibility of proteoses and peptones, | 77 | | Absorption of peptones from the living stomach, | 79 | | Differences between natural digestion in the stomach and artificial proteolysis, | 80 | | Relative formation of proteoses and peptones in the living stomach, | 81 | | Gastric digestion merely a preliminary step in proteolysis, | 81 | | Intestinal digestion alone capable of accomplishing all that is necessary for the complete nourishment of an animal, | 82 | | Some physiological properties of proteoses and peptones, | 83 | | The experiments of Schmidt-MÜlheim and Fano on the action of peptones when injected into the blood, | 84 | | Physiological action of albumoses, | 85 | | Introduction of albumoses into the blood, | 87 | | Proteose-like nature of the poisons produced by bacteria, | 89 | | The acrooalbumoses formed by the tubercle-bacillus, | 90 | | Toxic nature of proteoses and peptones, | 91 |
LECTURE III. Proteolysis by trypsin—Absorption of the main products of proteolysis. | Proteolysis by trypsin, | 93 | | Comparison of pepsin and trypsin, | 94 | | Trypsin especially a peptone-forming ferment, | 95 | | The primary products of trypsin-proteolysis, | 95 | | Scheme of trypsin-digestion, showing the relationship of the products formed, | 96 | | The fate of hemi-groups in trypsin-proteolysis, | 97 | | The primary products of trypsin-digestion mainly antibodies, | 98 | | Character and composition of antipeptones, | 99 | | Antialbumid as a product of pancreatic digestion, | 100 | | The peculiar action of trypsin in the formation of amido-acids, etc., | 101 | | Formation of lysin and lysatin in pancreatic digestion, | 103 | | The relationship of lysatin to urea, | 105 | | Formation of tryptophan or proteinochromogen by trypsin, | 105 | | Appearance of ammonia in trypsin-proteolysis, | 107 | | Relationship between artificial pancreatic digestion and proteolysis in the living intestine, | 109 | | Leucin and tyrosin products of the natural pancreatic digestion in the intestine, | 112 | | The physiological significance of leucin and tyrosin, | 113 | | Absorption of the main products of proteolysis, | 116 | | Absorption of acid-albumin, alkali-albuminate, etc. | 117 | | Absorption limited mainly to the intestine, very little absorption from the stomach, | 119 | | The change which the primary products of proteolysis undergo in the process of absorption, | 120 | | Peptones not present in the circulating blood, | 121 | | The change which peptones and proteoses undergo by contact with the living mucous membrane of the small intestine, | 122 | | Retrogression of peptones by contact with other living cells, etc., | 125 | | Functional activity of leucocytes in absorption, | 128 | | Digestive leucocytosis incited by nuclein, | 131 | | Shore’s experiments on the ability of lymph-cells to assimilate either proteoses or peptones, | 133 | | Lymph a true secretion from the blood-vessels, | 134 | | Direct excitatory effect of peptones when present in the blood on the endothelial cells, | 136 | | Selective activity of endothelial cells, | 137 |
DIGESTIVE PROTEOLYSIS
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