Structure of porcine pancreatic

The interactions of a-amylases, mainly porcine pancreatic a-amylase, and thiomaltodextrins have been investigated. In 1980, the 3-D structure of porcine pancreatic a-amylase was reported [68], and an analogue of the thiomdtotrio-side (48b), prepared by standard condensation between (34e) and (51c), was effective to label the active site and to identify a second binding site on the siu -face of the protein molecule. 

Figure 7.9 Topological structures of a-amylase A. Two-dimensional representation of the secondary and domain structures of porcine pancreatic a-amylase. Alpha helices are represented as circles and (3-strands in the up-direction as squares, and in the down direction as double squares. The (a/(3)g—TIM barrel comprises domain A. Hydrogen bonds between (3-strands are shown by dashed lines. The a-helices and (3-strands are identified in the various domains by A, B and C. (Reprinted by permission ofthe authors M. Qian et al.120) Two-dimensional representation ofthe secondary and domain structures of barley malt a-amylase (AMY2-2). Alpha helices are represented as cylinders and (3-strands as arrows. The (a/(3)g—TIM barrel comprises domain A, with eight (3-strands and an equivalent of eight a-helices. The active-site is composed ofthe loops that connect the C-termini ofthe (3-strands to the N-termini ofthe peripheral a-helices. (Adapted from A. Kadziola et al.121)...

X-ray crystallographic study of barley malt a-amylase has shown that it also has three domains in which the largest domain, domain A, also has a ((3/a)8-barrel structure, composed of amino acid residues 1 to 88 and 153 to 350.122 Domain B is composed of 64 residues (88 to 152) that are an excursion from the third (3-strand and the third a-helix, similar to the structure of porcine pancreatic a-amylase. Domain C occurs at the C-terminus and is composed of 53 residues (351 to 403) that are arranged into a five-strand (3-sheet. 

Figure 5. Amino acid sequence and secondary structure of porcine pancreatic prophospholipase (20)...

Itasaka, O. Hori, T. (1979) Studies on Glycosphingolipids of Fresh-water Bivalves V. The Stmeture of a Novel Ceramide Octasaccharide Containing Mannose-6-phosphate Found in the Bivalve Corbicula sandaP, Journal of Biochemistry (Tokyo), 85,1469-81 Jackson, R.L. Hirs, C.H.W. (1970) The Primary Structure of Porcine Pancreatic Ribonuclease. I. The Distribution and Sites of Carbohydrate Attachment , Journal of Biological Chemistry, 245, 624-36... 

Vijayalakshmi, J. Meyer, E. F. Kam, C.-M. Powers, J. C. Structural study of porcine pancreatic elastase complexed with 7-amino-3-(2-bromoethoxy)-4-chloroisocoumarin as a nonreactivable doubly covalent enzyme-inhibitor complex. Biochemistry 1991, 30, 2175-2183. 

Structure-Function Dissection and sequence analysis of phospholipases A2, 197, 201 cloning, expression, and purification of porcine pancreatic phospholipase A2 and mutants, 197, 214 preparation of antibodies to phospholipases A2, 197, 223 thermodynamics of phospholipase A2-ligand interactions, 197, 234 activation of phospholipase A2 on lipid bilayers, 197, 249 ... 

Figure 2 Structure of human pancreatic lipsse with indication of the active site buried beneadt a mobile Tip 232 surface loop (flap) In order to give access to (he substrate aod Ihe vwipwrbindLTg sits laced is ihe sir direct 1 i the tjw tite. The ennrma is glycosylated at Asa 166 (porcine), subiliatd at tbe surface segment by a Ca +-bJnding site (partly hidden, marked by an asterisk), and can be anchored by means of the hepaiirebinding site fa heparan sulfate on cell surfaces (Rom Ref. 8.)...

Powers JC, Oleksyszyn J, Narasimhan SL, Kam C-M, Radhakrishnan REF, Meyer J (1990) Reaction of Porcine pancreatic elastase with 7-substituted 3-alkoxy-4-chloroisocoumarins design of potent inhibitors using the crystal structure of the complex formed with 4-chloro-3-ethoxy-7-guanidinoisocoumarin. Biochemistry 29 3108-3118... 

The catalytic activity of porcine pancreatic a-amylase, another member of the glucosyl hydrolase family, is metal cofactor-dependent [53]. A calcium ion-binding site is located at the interface of an antiparallel f-sheet, inserted in one of the loop regions of the /ia-barrel, and the core structure. In the calcium-bound state, the insertion stabilizes the substrate-binding site, and indirectly constrains part of the active site in a catalytically competent conformation. 

Mattos, C., Giammona, D. A., Petsko, G. A. and Ringe, D. (1995) Structural analysis of the active site of porcine pancreatic elastase based on the X-ray crystal structures of complexes with trifluoroacetyl-dipeptide-anilide inhibitors. Biochemistry, 34, 3193-3203. 

Pharmaceutical companies are increasingly interested in developing products based on proteins, enzymes, and peptides. With the development of such products comes the need for methods to evaluate the purity and structural nature of these biopharmaceuticals. Proteins, unlike traditional pharmaceutical entities, rely on a specific secondary structure for efficacy. Methods to monitor the secondary structure of pharmaceutically active proteins, thus, is necessary. Infrared spectroscopy provides a way to study these compounds quickly and easily. Byler et al. (65) used second-derivative IR to assess the purity and structural integrity of porcine pancreatic elastase. Seven different lyophilized samples of porcine pancreatic elastase were dissolved in D20, placed in demountable cells with CaF2 windows, and IR spectra obtained. The second derivatives of the spectra were calculated and the spectral features due to residual water vapor and D20 removed. 

Figure 3 shows the structure of the HPL-colipase complex [30,34]. Human pancreatic lipase consists of 449 amino acid residues and has 85% homology with that of porcine pancreatic lipase. Two distinct domain exists in HPL, that is, a larger N-terminal domain (N-domain) comprising 1-335 residues and a smaller C-terminal domain (C-domain). Of these domains, the N-domain con-... 

Evidence has been reported for the presence of inhibitors of porcine pancreatic a-amylase in rye and wheat. The inhibitors were isolated by affinity chromatography on the agarose derivative-immobilized enzyme. The location in the seed, molecular properties, and biological role of proteinaceous inhibitors of a-amylase in wheat have been reviewed. Inhibition specificity of albumin inhibitors and structural features essential for interaction with inhibited amylases were also examined. The possible significance of these naturally occurring inhibitors in relation to their presence in foods in active form was described. 

Marangoni, A.G. 1993 Effects of the interaction of porcine pancreatic lipase with AOT/isooctane reversed micelles on enzyme structure and function follow predictable patterns. Enzyme Microb. Technol. 15, 944-949. 

Traditionally, glucagon preparations utilized therapeutically are chromatographically purified from bovine or porcine pancreatic tissue. (The structure of bovine, porcine and human glucagon is identical, thus eliminating the possibility of direct immunological complications). Such commercial preparations are generally formulated with lactose and sodium chloride and sold in freeze-dried form. Glucagon, 0.5-1.0 units (approximately 0.5-1.0 mg freeze-dried hormone), is administered to the patient by s.c. or i.m. injection. 

The ultimate objective of an X-ray cryoenzymological study is the mapping of the structures of all kinetically significant species along the reaction pathway. In the case of ribonuclease A this has been largely achieved, as described above. Other enzymatic reactions now await application of the same techniques. Unfortunately, not all crystalline enzymes lend themselves to study by this method. In some cases it may be impossible to find a suitable cryoprotective mother liquor in others, the reaction may occur too rapidly at ordinary temperature. A reaction with Acat of 10 seconds and an activation enthalpy of —6 kcal mol will not be quenched even at — 75°C. The approach we have described in this article can be applied to only a small number of enzymes. Two likely candidates for successors to ribonuclease are the enzymes yeast triosephosphate isomerase and porcine pancreatic elastase. 

L.H. Takashashi, R. Radhakrishnan, R.E. Rosenfield, E.F. Meyer, D.A. Trainor, Crystal structure of the covalent complex formed by a peptidyl a,a-difluoro- -keto amide with porcine pancreatic elastase at 1.78 A resolution, J. Am. Chem. Soc. Ill (1989) 3368-3374. 

The investigations carried out by Professor French and his students were based on sound experimental approaches and on intuitive theoretical considerations. The latter often resulted in new experiments for testing a hypothesis. On the basis of theoretical considerations, Professor French proposed a model for the structure of the amylopectin molecule, and the distribution of the linear chains in this molecule. This model was tested by utilizing enzymes that selectively cleave the linear chains, and the results substantiated the theoretical deductions. He proposed a theory on the nature and types of reactions occurring in the formation of the enzyme - starch complex during the hydrolysis of starch by amylases. In this theory, the idea of multiple attack per single encounter of enzyme with substrate was advanced. The theory has been supported by results from several types of experiments on the hydrolysis of starch with human salivary and porcine pancreatic amylases. The rates of formation of products, and the nature of the products of the action of amylase on starch, were determined at reaction conditions of unfavorable pH, elevated temperatures, and increased viscosity. The nature of the products was found to be dramatically affected by the conditions utilized for the enzymic hydrolysis, and could be accounted for by the theory of the multiple attack per single encounter of substrate and enzyme. 

Enantiomerically pure cyclopropanes are a frequent motif in the structure of natural products. Their synthesis is often demanding and many approaches have been made [50, 51]. Porcine pancreatic lipase (PPL) was used for the stereoselective desymmetrization of a cyclopropane dibutanoate (Fig. 2). The asymmetric hydrolysis of the meso compound yielded the corresponding enantiopure alcohol almost quantitatively. The intermediate obtained was successfully applied in the total synthesis of dictyopterenes A and C, sexual pheromones of brown algae [52], and constanolactones (see below) [53]. 

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