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C Figarella

Publications and source records attributed to C Figarella.

At least 127 records · Page 7Linked to original sources
PubMed1979

Comparative studies on the mechanism of activation of the two human trypsinogens.

The activation of human trypsinogens 1 and 2 by porcine enterokinase at pH 5.6 shows that the two human zymogens are equivalent substrates for this enzyme and that both proteins are activated faster than the cationic bovine trypsinogen. At pH 8.0 and in the presence of 20 mM calcium the two human trypsinogens are activated by either human trypsin at the same rate but the affinity of both trypsins is higher for trypsinogen 1 than for trypsinogen 2. Two Ca2+ binding sites are identified in the two human zymogens and their pK(Ca2+) values determined. For trypsinogen 1 the values are respectively of 2.8 and 3.3 for the primary and secondary Ca2+ binding sites, and for trypsinogen 2 of 3.4 and 2.7. These values are markedly different from those obtained for bovine cationic trypsinogen, especially in the case of trypsinogen 1. These results point out a different degree of saturation of the calcium binding sites of the 2 human zymogens that must exist in physiological conditions, suggesting different biological activities of the two trypsinogens.

Binding Sites↗
PubMed1979

The two human trypsinogens. Evidence of complex formation with basic pancreatic trypsin inhibitor-proteolytic activity.

The formation of complexes between human trypsinogens and the basic pancreatic trypsin inhibitor is demonstrated by using affinity chromatography on Sepharose coupled to basic pancreatic trypsin inhibitor. This interaction indicates the pre-existence of the active site in human trypsinogens. This active site induces the proteolytic activity of the two zymogens which activate spontaneously at pH 5.6 and pH 8.0 before and after affinity chromatography. The effect of affinity-chromatography on trypsinogen spontaneous activation is not the same on trypsinogens 1 and 2. A striking difference appears between the activation of the two trypsinogens. In all cases, trypsinogen 1 autoactivates more rapidly than trypsinogen 2, except at pH 5.6 in the presence of 10 mM Ca2+, which inhibits the autoactivation of trypsinogen 1. The effect of inherent proteolytic activity of human trypsinogens is discussed in relation to pathological conditions of enterokinase deficiency and acute pancreatitis.

Calcium↗
PubMed1979

Characterization and purification of a kallikrein from human pancreatic juice and immunological comparison with other kallikreins.

A prekallikrein has been demonstrated in human pancreatic juice and the active enzyme has been purified from this material. The purification procedure included filtration on Sephadex G-100, chromatography on DEAE-cellulose and affinity chromatography on trypsin-inhibitor Sepharose. The purified kallikrein appeared to be homogeneous by polyacrylamide gel electrophoresis at pH 8.3 and by immunoelectrophoresis. Human pancreatic kallikrein is immunologically different from human plasma kallikrein and from pancreatic kallikreins of other species (hog, cat, rat and dog). Human pancreatic kallikrein has common antigenic determinants with human urinary and submandibular kallikreins but probably not with parotid kallikrein.

Animals↗
PubMed1978

Purification and characterization of a carboxyl ester hydrolase from human pancreatic juice.

A carboxyl ester hydrolase has been purified 20-fold from human pancreatic juice. It is a glycoprotein with a molecular weight of 100 000. It contains 9% neutral and amino carbohydrates and the amino acid composition is characterized by a high content of proline residue (12.7%). The enzyme catalyzes the hydrolysis of p-nitrophenylacetate and the activity increases in the presence of biliary salts; V is not modified but Km is decreased 10 times by addition of biliary salts. The enzyme migrates on Sephadex G-200 as a protein with a molecular weight of 300 000. This behaviour does not seem to be due to a polymerization but to a peculiar configuration of the enzyme.

Amino Acids↗
PubMed1978

The two human trypsinogens: catalytic properties of the corresponding trypsins.

The catalytic properties of the two human trypsins obtained from purified trypsinogens have been studied. The catalytic rate constant kcat and the pK of the ionisable residue implicated in the active site have been determined with Bz-Arg-OEt. The hydrolysis of Tos-Arg-OMe by human trypsins does not follow the simple Michaelis-Menten scheme and indicates a difference in the conformational flexibility of the active site-regions of the two enzymes. Both enzyme are readily autolyzed and calcium ion plays a fundamental role in stabilizing trypsin activity. However trypsin 2 self-digests more rapidly than trypsin 1. These results are a prerequisite to the elucidation of the fate of pancreatic enzymes in human digestive tract.

Animals↗
PubMed1978

Two human trypsinogens. Purification, molecular properties, and N-terminal sequences.

The two human trypsinogens have been isolated from human pancreatic juice in a sufficient amount to study molecular and structural properties. The purification procedure included filtration on Sephadex G-100 followed by ion-exchange chromatography on DEAE-cellulose. The two trypsinogens represent 19% of total proteins of pancreatic juice. Trypsinogen 1, the major form, is present in a quantity twice that of trypsinogen 2, which is the most anionic protein in human pancreatic juice. The two proteins have partial immunological identity, close molecular weights (23 438 and 25 006 for trypsinogens 1 and 2, respectively) and similar amino acid compositions. The N-terminal sequences are the same for the first 9 residues: Ala-Pro-Phe-Asp4-Lys-Ile. The two proteins differ in the activation peptides released during the transformation to trypsins. Trypsinogen 2 liberates one octapeptide Ala-Pro-Phe-Asp4-Lys while trypsinogen 1 liberates two peptides, the same octapeptide and the pentapeptide (Asp)4-Lys.

Amino Acid Sequence↗
PubMed1978

Comparison of the kininogenase activity of human pancreatic trypsins and porcine Kallikrein on Met-Lys-bradykinin and human plasma kininogen.

Human trypsins 1 and 2 both converted Met-Lys-bradykinin to bradykinin and released bradykinin from kininogen in human plasma as measured by bioassay with the isolated guinea pig ileum. Porcine kallikrein did not act on Met-Lys-bradykinin and released kallidin from human kininogen. Since human trypsin 1 is only partially and trypsin 2 completely inhibited by soybean trypsin inhibitor, these data show that the criterion of susceptibility to soybean trypsin inhibitor cannot be used to discriminate between trypsin and kallikrein of different species.

Animals↗
PubMed1978

Lipase activity in blood following endoscopic pancreatography: demonstration of its pancreatic origin and existence of ductal or acino-venous pathways in man.

The presence of a lipase activity has been observed in the blood of patients undergoing an endoscopic retrograde cholangio-pancreatography (ERCP). The identity between this serum lipase and pancreatic lipase has been demonstrated by their similarity in in chromatographic, immunological, and catalytic properties. Lipase activity in serum increased when pancreatography was accompanied by a passage of the contrast medium to the kidney demonstrating the presence of ductal or acino-venous pathways in man.

Cholangiography↗
PubMed1977

Human pancreatic lipase: a glycoprotein.

Human lipase has been purified from pancreatic juice. The protein has a molecular weight of 48 000 and an N-terminal residue of lysine. It has been characterized as a glycoprotein containing 4.7 mol of glucosamine, 2.8 mol of mannose, 2.9 mol of fucose, 3.0 mol. of galactose and 1.1 mol of glucose per mol of protein. Two isolipases have been separated by polyacrylamide gel electrophoresis. Their isoelectric points are 5.80 and 5.85, respectively and both are glycoproteins. Immunological cross reactions have been obtained between human lipase and other mammalian lipases (porcine, bovine, ovine, canine and rat).

Amino Acids↗