Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The specificity and mode of action of an acid proteinase (EC 3.4.23.6) from Aspergillus saitoi were investigated with oxidized B-chain of insulin, angiotensin II and bradykinin. Further purification of acid proteinase was performed with N,O-dibenzyloxycarbonyl-tyrosine hexamethylene-diamino-Sepharose 4B affinity chromatography and isoelectric focusing. The purified enzyme was free of any other proteolytic activity demonstrated in Asp. saitoi. Acid proteinase from Asp. saitoi hydrolyzed primarily two peptide bonds in the oxidized B-chain of insulin, the Leu(15)-Tyr(16) bond and the Phe(24)-Phe(25) bond. Additional cleavages of the bonds His(10)-Leu(11), Ala(14)-Leu(15) and Tyr(16)-Leu(17) were also noted. Primary splitting sites at Leu(15)-Tyr(16) and Phe(24-)-Phe(25) with acid proteinase from Asp. saitoi were identical with those reported in the work of cathepsin D (EC 3.4.23.5) from human erythrocyte. Hydrolysis of angiotensin II was observed at the Tyr(4)-Ile(5) bond. In conclusion, peptide bonds which have a hydrophobic amino acid such as phenylalanine, tyrosine, leucine and isoleucine in the P'1 position (as defined by Berger and Schechter, [29]) are preferentially cleaved by the trypsinogenactivating acid proteinase from Asp. saitoi.
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PMID:Purification of an acid proteinase from Aspergillus saitoi and determination of peptide bond specificity. 2 99

The use of derived and synthetic peptides has contributed greatly to our understanding of encephalitogenic determinants in the basic protein molecule. Peptides derived from BP by use of trypsin, pepsin, cathepsin D (brain and liver) and BNPS-skatole have proven most useful. Synthetic peptides have served to define the disease-inducing determinants with precision. A remarkable feature of these studies is that different antigenic determinants serve as encephalitogenic sites in different species. The encephalitogenic sites comprise short peptide domains of the BP polypeptide chain, only 8 residues (rat), 9 residues (guinea pig), and 10 residues (rabbit) in length. In view of the requirement for both haptenic and carrier specificity of an immunogenic molecule, it is impressive that these peptides themselves elicit the autoimmune disease, EAE. While less active than BP on a molar basis, they are nonetheless potent encephalitogens, producing clinical signs in rats and guinea pigs at less than 1 microgram dose. The data indicate that for most animal species (guinea pig, rat, monkey) there appears to be only one major encephalitogenic determinant, an unusual finding in view of the number of antigenic determinants for cell-mediated immunity existing in the BP molecule. Possibly a combination of genetic and anatomical factors may account for this phenomenon. A relationship may exist between multiple sclerosis and EAE as shown by peptide studies; lymphocytes are found in MS patients during exacerbation sensitized to the same region of BP active in the monkey. The major encephalitogenic sites are: Guinea Pig (9) Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys(Arg); Rabbit (10) Thr-Thr-His-Tyr-Gly-Ser-Leu-Pro-Gln-Lys; Rat (8) Ser-Gln-Arg-Ser-Gln-Asp-Glu-Asn; Monkey (14) Phe-Lys-Leu-Gly-Gly-Arg-Asp-Ser-Arg-Ser-Gly-Ser-Pro-Hser.
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PMID:Peptides and autoimmune disease. 8 85

The purity of cathepsin D has been increased from 150 units/mg to over 200 units/mg. Peptides such as Ala-Phe-NH2, His-Phe-NH2 and Phe-Phe were split by impure enzyme and activity was blocked by pepstatin and diazoacetylnorleucine methyl ester. Pure preparations no longer digested these peptides. This points to the presence of a second peptidase activity similar to cathepsin D in specificity and inhibition properties, but distinct from it . Cathepsin D splits the peptides Leu-Phe-NH2, Leu-Tyr-NH2, Ac-Phe-TyrI2, and Ala-Leu-Tyr-Leu upon overnight incubation. More rapid splitting is found with phenyl sulfite, Glu-Ala-Leu-Tyr-Leu-Val, and Bz-Arg-Gly-Phe-Phe-Leu-4-methoxy-beta-naphthylamide. Digestion of bovine hemoglobin and human serum albumin by ruptured rat liver tritosomes was studied over the pH range 2.5-6.5. The combined action of cathepsin D and thiol proteinases accounted for most of the digestion. Cathepsin D accounted for 75% of the hemoglobin digestion at pH 3 and 45% at pH 5. Thiol proteinase accounted for 85% of the albumin digestion at pH 5. The role of cathepsin D in the development of embryonic limbs and skin, in uterine involution, and in cartilage degradation was reviewed. The activity of cathepsin D on cartilage matrix proteoglycans is limited to acid pH values. Human articular cartilage also contains metalloproteases active at pH 4.5 and 5.7.
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PMID:Specificity and biological role of cathepsin D. 59 4

Cathepsin B and cathepsin D were purified from rat liver and skeletal muscle. Electrophoretic analyses revealed that the enzymes were highly purified, and isoelectric focusing demonstrated multiple forms of both enzymes. Purified actin and myosin, as well as actin and myosin in myofilaments and myofibrils, were degraded by the purified cathepsins B and D. Degradation of myosin was completely blocked by the cathepsin B and D inhibitors, leupeptin and pepstatin, respectively. Cathepsins B and D were visualized by electron microscopy, using CBZ-Ala- Arg-Arg-4-methoxy-beta-naphthylamine and BZ-Arg-Gly-Phe-Leu-4-methoxy-beta-naphthylamine as substrates.
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PMID:Degradation of myofibrillar proteins by cathepsins B and D. 61 6

The NH2-terminal heterogeneity which is generated in bovine GH during its extraction from mildly acidified pituitary homogenates is attributable to a newly identified peptidase. The beta-naphthylamide of Phe-Pro-Ala, modeled after the NH2-terminal tripeptide sequence of the phenylalanyl monomer of bovine growth hormone, was cleaved by the peptidase into the tripeptide and B-naphthylamine and served as a substrate for assay of the eznyme. However, the B-naphthylamide of Ala-Phe-Pro, modeled after the NH2-terminal tripeptide sequence of the alanyl monomer, was not cleaved. In harmony with this specificity, the peptidase cleaved 11 tripeptides sequentially from the NH2-terminus of the phenylalanyl monomer of bovine GH but none from the alanyl monomer. Six of the tripeptides nearest the NH2-terminus were unequivocally identified and their sequences were consistent with the NH2-terminal octadecapeptide sequence of the phenylalanyl monomer of bovine GH. Five additional peptides were by composition consistent with their being tripeptides derived from residues 19--33. Because of the apparent specificity for the hydrolytic release of tripeptides and inability to cleave substituted tripeptidyl derivatives, the enzyme is considered to be a tripeptidyl aminopeptidase. In its hydrolysis of phenylalanyl monomers of rat growth hormone, a similar number of tripeptides was released, associated with which there was a 70% loss of biological activity but no reduction in immunological activity. The enzyme could be solubilized by extraction with 1% Triton X-100 at pH 3.0, precipitated between 2 and 3 M (NH4)2SO4, and further purified by gel filtration on G-75 in M/10 acetic acid. The enzyme has a mol wt of 57,000 and is optimally active at pH 4. It can be differentiated from cathepsin D by its insensitivity to inhibition by pepstatin.
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PMID:Identification of a tripeptidyl aminopeptidase in the anterior pituitary gland: effect on the chemical and biological properties of rat and bovine growth hormones. 74 18

Net changes in the concentrations of 18 amino acids in perfusate and skeletal muscle were followed during perfusion of hemicorpus preparations from fed rat. Perfusate levels of 16 amino acids showed little change from their initial concentrations during the 1st h, but increased dramatically during the 2nd and 3rd h. Aspartate and glutamate levels decreased continuously throughout the perfusion. Release of alanine and glutamine accounted for approximately 50% of the total change in perfusate amino acids. The increase in perfusate amino acids was derived from net breakdown of muscle proteins and not from leakage from the intracellular pool as evidenced by elevated concentrations of intracellular amino acids in perfused muscle. Addition of insulin to the perfusate did not change the pattern of amino acid release during the 1st h of perfusion. However, during the 2nd and 3rd h the hormone completely prevented the net release of most amino acids and maintained intracellular concentrations of most amino acids at levels found in upperfused tissue. Effects of time of perfusion and insulin on amino acid release were accounted for by changes in the rate of protein turnover. Protein synthesis in gastrocemius and psoas muscles in control perfusions decreased after 1 h to approximately 50% of the initial rate. This decrease was accompanied by a 2-fold increase in the level of ribosomal subunits, indicating development of a block in peptide chain initiation. Addition of insulin maintained the initial rate of synthesis and the in vivo level of ribosomal subunits, demonstrating that the hormone prevented the block in peptide chain initiation from forming. Addition of insulin after 2 h reversed the perfusion-induced block in initiation. Synthesis of the specific muscle protein myosin was increased 45% over the control rate in the presence of insulin. Insulin also produced a 50% decrease in the rate of protein degradation during the 2nd and 3rd h of perfusion. A similar effect was noted when protein synthesis was inhibited by addition of cycloheximide. Higher concentrations of insulin were required to maximally inhibit protein degradation than to increase protein synthesis. Involvement of lysosomal proteases in the effect of insulin on protein degradation was evaluated by measuring cathepsin D activity in psoas muscle homogenates. "Free" enzyme activity increased as a result of perfusion while addition of insulin maintained this activity at the unperfused level. Neither perfusion nor insulin had any effect on total cathepsin D activity. Alterations in protein degradation and lysosomal enzyme activity were not due to changes in levels of adenine nucleotides, GTP, or creatine phosphate.
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PMID:Regulation by insulin of amino acid release and protein turnover in the perfused rat hemicorpus. 83 25

1. The proteolytic processing sites of human lysosomal aspartic protease cathepsin D at which the intermediate single-chain form was converted into the mature two-chain form were determined. 2. The two chains were isolated by reversed-phase HPLC in order to investigate the cleavage sites of the enzyme. 3. Protein sequencing of the heavy chain, which was presumed to be derived from the C-terminal side in the single-chain enzyme, gave an N-terminal Leu 105. In addition, it revealed that there were also minor sequences, which commenced with Gly 106 and Gly 107. 4. A small C-terminal peptide was isolated from the light chain, which had been digested with two kinds of exogenous proteases. Sequence determination of this peptide, which was characterized as a nonapeptide by mass spectrometry, suggested that the C-terminus of the light chain was Ser 98. 5. These results indicate that a Ser 98-Ala 99 bond and an Ala 104-Leu 105 bond are cleaved to release 6 amino acid residues between the two chains.
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PMID:Proteolytic processing sites producing the mature form of human cathepsin D. 142 30

Urokinase (u-PA) proteolytically cleaves both human plasma (pFn) and cellular (cFn) dimeric fibronectin (M(r) 440,000) into four major polypeptides of approximately M(r) 210,000, 200,000, 25,000, and 6,000. Amino acid sequence analysis of the polypeptide fragments indicated that the enzymatic cleavage of Fn occurs at two sites: 1) between an arginine/alanine peptide bond located C-terminal to residue 259; this cleavage liberates the N-terminal M(r) 25,000 fragment and the M(r) 210,000 and M(r) 200,000 polypeptides derived from the A and B chains of Fn, respectively; and 2) between an arginine/threonine peptide bond located C-terminal to residue 2,299, thereby yielding an M(r) 6,000 dimeric fragment containing the C-terminal interchain disulfide bonds. Predigestion of Fn with u-PA increased the molecule's vulnerability to further attack by the enzymes plasmin and cathepsin D. These data provide further biochemical evidence for the proteolytic cleavage of fibronectin by plasminogen activators and substantiate that u-PA digestion of Fn may be an initial event in the local degradation of the extracellular matrix by malignant cells, possessing elevated levels of these enzymes.
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PMID:Localization of the cleavage sites on fibronectin following digestion by urokinase. 146 74

Observing activity of some lysosomal enzymes in blood serum and leucocytes of rabbits subjected to injection of 200,000 units of retinol and 25 mg of hydrocortisone/kg of body weight it was found that: 1. In the effect of retinol administration there was an increase in the activity AP, BGAL, BGLU, AspAT and lipase in blood serum after 72 hours and NAGL after 168 hours while in leucocytes BGAL and NAGL after 72 hours and AGAL after 168 hours. 2. As a result of hydrocortisone injection the activity of all the enzymes examined (except Ala-Na) in blood serum increased markedly already after 24-48 hours. 3. In leucocytes hydrocortisone caused a significant increase in the activity of AP, BGRD, NAGL, BGAL, AGAL and cathepsin D. 4. The glucose level in blood plasma decreased after 48 hours and 120 hours after hydrocortisone injection and 168 hours after retinol injection.
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PMID:Activity of some lysosomal enzymes in plasma and leucocytes of rabbits exposed to effect of retinol and hydrocortisone. 161 54

Lysosomal enzymes contain a common protein determinant that is recognized by UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase, the initial enzyme in the biosynthesis of mannose-6-P residues. Previously, we generated a lysosomal enzyme recognition domain by substituting two regions (lysine 203 and amino acids 265-292) of the lysosomal hydrolase cathepsin D into a related secretory protein glycopepsinogen. When expressed in Xenopus oocytes, the oligosaccharides of the chimeric protein were efficiently phosphorylated (Baranski, T. J., Faust, P. L., and Kornfeld, S. (1990) Cell 63, 281-291). In the current study, incremental substitutions of cathepsin D residues into glycopepsinogen and alanine-scanning mutagenesis were utilized to define the recognition domain more precisely. A computer-generated model of the cathepsin D/pepsinogen chimeric molecule served as a guide for mutagenesis and for the interpretation of results. These studies indicate that the recognition domain is a surface patch that contains multiple interacting sites. There is a strict positional requirement for the lysine residue at position 203.
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PMID:Mapping and molecular modeling of a recognition domain for lysosomal enzyme targeting. 166 Apr 71


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