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Biomedical subjects

W N Kuo

Publications and source records attributed to W N Kuo.

At least 19 recordsLinked to original sources
PubMed1992

Regulation of Staphylococcus protease using complement, interferon and immunoglobulin as substrates.

The effects of various agents on the cleavage of serum albumin, interferon, immunoglobulin and complement component C1q by the extracellular protease from Staphylococcus aureus were analysed by SDS-polyacrylamide gel electrophoresis. Arachidonic acid moderately stimulated the proteolysis of serum albumin, interferon and complement component. Phosphatidic acid effectively enhanced the proteolysis of serum albumin and IgG, whereas it inhibited the cleavage of IgM. The proteolysis of IgG was appreciably enhanced by sphingosine. In contrast, phosphatidyl choline and phosphatidyl glycerol were shown to have an inhibitory effect on the proteolysis of IgG and IgM. Phosphatidyl serine, phosphatidyl inositol and phosphatidyl ethanolamine also inhibited the proteolysis of IgG. The failure of any of these agents to exert a persistent effect on the cleavage of all substrates, revealed the complexity of the interactions among the agent, the substrate and the protease.

Complement C1q↗
PubMed1991

Regulation of fungal proteolysis on cyclic AMP-dependent protein kinase, cyclic AMP phosphodiesterase, glycogen synthase and histones.

Limited proteolysis of catalytic and regulatory subunits of cyclic AMP-dependent protein kinase (A-pk), cyclic AMP phosphodiesterase, glycogen synthase, and histones by fungal protease (type XIX) was analyzed by the digested peptide bands in SDS polyacrylamide gel electrophoresis. The modulatory effects on proteolysis by nucleotides, polypeptides, and phospholipids may greatly depend on the intrinsic nature of substrates. The proteolysis of the regulatory subunit of A-pk and glycogen synthase was not regulated by nucleotides and nucleic acids. In comparison, phosphatidyl serine, cardiolipin, and pepstatin A stimulated the proteolysis of the catalytic subunit of A-pk. Whereas, lambda DNA (Hind III digest), t-RNA, GTP-, phosphatidyl serine, sphingosine inhibited the proteolysis of cyclic AMP phosphodiesterase. Moreover, MS2 RNA, lambda DNA, t-RNA, dGTP, Phosphatidyl serine, phosphatidyl inositol, antipain, and chymostatin exerted inhibitory proteolytic effect on histone VIII-S. Some of these agents also had similar inhibitory effect on other types of histones (types III-S and VII-S). The inhibitory effect of phosphatidyl serine on proteolysis of histone may be due to their interaction which was monitored by the drastic increase of uv absorbance.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1991

Proteolysis of interleukin-2, interferon and immunoglobulin by venoms.

Limited proteolysis by venoms was analysed by the cleaved peptide band(s) in SDS-polyacrylamide gel electrophoresis. The venom from Crotalus atrox degraded interferon, interleukin-2, IgG, IgM, and a crude form of acetyl cholinesterase but had no effect on IgA. Although the venom from Androctonus australis did not exert appreciable proteolysis on any of the immunoglobulins it had potent proteolytic activities against interferon and interleukin-2. The venom from Vespula maculifrons had only a minor proteolytic effect on interferon. The proteolysis by venoms was not effectively inhibited by alpha 1-antitrypsin or a2-macroglobulin. Moreover, no appreciable proteolytic activity was detected in the venoms from Bufo arenarum, Apis mellifera and Heloderma suspectrum.

Animals↗
PubMed1990

Stimulation of proteolysis on calmodulin.

The proteolysis of calmodulin by fungal protease (type XIX) was greatly enhanced in the presence of dGTP and MS2 RNA. Whereas, only moderate proteolytic activation on bacterial proteases (type XXVI) was observed in the presence of MS2 RNA. No appreciable proteolysis of calmodulin by bacterial protease (type IX) was observed. Proteolytic fragments of calmodulin cleaved by fungal protease exhibited unusual low mobility during SDS-polyacrylamide gel electrophoresis. Similar decreased electrophoretic mobility was also noted in the proteolytic fragments of other Ca2(+)-binding proteins including S-100A protein and parvalbumin.

Animals↗
PubMed1990

A further study on the regulation of microbial proteases.

Various agents were tested for their effects on microbial proteases, which activity was monitored by the analysis of cleaved peptide bands in SDS-polyacrylamide gel electrophoresis. Using casein as a substrate, fungal protease (type XIX) was inhibited by the phenyl methyl sulphonyl fluoride, chymostatin, antipain and leupeptin, while bacterial protease (type XXVI) was inhibited by phosphatidyl glycerol, phosphatidyl inositol and sphingosine. MS2 RNA exerted minor inhibition on the bacterial proteolysis of regulatory subunits of cyclic AMP-dependent protein kinase (A-PK). The cleavage of DNA binding protein by both proteases was inhibited, in the presence of MS2 RNA and lambda DNA. In comparison, phosphatidyl serine slightly stimulated the fungal protease on the cleavage of ribonuclease T1. RNA polymerase is a good substrate of the bacterial protease as indicated by the generation of multiple cleaved peptide fragments, whereas alkaline phosphatase is not susceptible to proteolysis.

Aspergillus↗
PubMed1990

Inhibitory effect of transfer RNA on protein kinases from baker's yeast and rat skeletal muscle.

Sephadex G-200 gel filtration of DNA cellulose-treated crude extracts of rat skeletal muscle, revealed a broad peak-fraction of tRNA-inhibitory protein kinases (PK) coeluted endogenous substrates. In comparison, the elution profile of baker's yeast exhibited multiple peak-fractions of tRNA-inhibiting PK. Various tRNA all showed inhibition to PK. In the presence of regulatory subunit of cyclic AMP-dependent protein kinase, tRNA did not exert synergetic inhibition on PK. Moreover, the interaction of tRNA with active muscle PK fractions could not be monitored by the increment of absorbance at 340 nm. tRNA had no significant regulatory effect on the phosphorylation of actin and myosin.

Animals↗
PubMed1989

Interaction between cortisol and microbial proteases.

Binding (or interaction) of cortisol with microbial molecule(s) was observed by employing Bio-Gel HTP affinity chromatography and subsequently by fluorescence spectrophotometry. Molecule(s) in the crude extract of baker's yeast and in other microbial proteases exhibited varied degrees of cortisol-binding. Bacterial protease (type IX) had highest, while the type XXVI enzyme had the lowest, binding capacity. In addition, these two proteases exhibited a distinct difference in the alterations of ultraviolet spectra due to interaction with cortisol. Using casein as a substrate, cortisol, CTP, trypsin inhibitor or leupeptin appreciably inhibited type IX protease at low concentrations of Ca2+. However, thyroxine had no effect on this protease.

Bacteria↗
PubMed1986

Regulatory effects of S-100 protein and parvalbumin on protein kinases and phosphoprotein phosphatases from brain and skeletal muscle.

In the eluted fractions of histone-treated crude extracts separated by Sephadex G-200 filtration, multiple protein kinase (PK) activities, including three from brain and two from skeletal muscle, were augmented by both S-100 protein and parvalbumin on the phosphorylation of endogenous substrates. One additional PK activity suppressed by both S-100 and parvalbumin was also found in muscle. In comparison, phosphoprotein phosphatases (PPase), which were also prepared by the same procedure of initial step of histone-treatment followed by the steps of Bio-Gel P-6DG for brain and DNA-cellulose for muscle, were all activated by S-100 while inhibited by parvalbumin and phosphatidylserine.

Animals↗
PubMed1986

Probable occurrence of brain basic protein factor I, an activator of phosphoprotein phosphatases.

Basic protein factor I (BPFI was purified to homogeneity from bovine brain by boiling and trichloroacetic acid-precipitation of tissue homogenate, followed by DEAE-cellulose, Sephadex G-150, Affi-Gel-phenothiazine, and Bio-Gel P-6DG chromatographic procedures. The preparation appeared as a single protein band in the SDS-polyacrylamide gel electrophoresis with a minimal Mr of 13,200. The factor was a basic protein as indicated by an estimated isoelectric point of pH 8.3 and a high content of amino acids including arginine, histidine, lysine and others. In the absence of Mn2+, the factor stimulated the phosphoprotein phosphatases (PPase) from rabbit brains. Unlike histones or protamine, the factor was a poor substrate for megamodulin-dependent protein kinase. In addition, the factor did not interact significantly with E. coli megamodulin.

Amino Acids↗
PubMed1986

Modulation of the catalytic subunit of cyclic AMP-dependent protein kinase by calmodulin, S-100 protein, parvalbumin and troponin.

The activity of the catalytic subunit of cyclic AMP-dependent protein kinase (A-PK), utilizing type II-S, III-S histone or protamine (free base) as a substrate, was augmented in the presence of regulatory protein including calmodulin, S-100 protein, parvalbumin, or troponin. However, inhibition by calmodulin or S-100 but stimulation by parvalbumin or troponin on this A-PK subunit was observed when II-S histone was replaced by V-S, VI-S, VII-S, or VIII-S histone. In addition, the stimulatory effect of calmodulin or S-100 on this A-PK subunit utilizing III-S histone was greatly diminished when half the dose of III-S was replaced by other histones in a bi-mixed form.

Animals↗
PubMed1985

Modulation of protein kinases and phosphoprotein phosphatases by a small acidic protein from bovine brains.

A small, acidic and heat-stable protein was purified from bovine brains by column chromatography on DEAE-cellulose, Bio-Gel HTP, Affi-Gel phenothiazine and Sephadex G-75. This protein stimulates megamodulin-dependent protein kinase I from brains and phosphoprotein phosphatases from either brain or yeast. However, it inhibits cyclic AMP-dependent protein kinases from skeletal muscle.

Animals↗
PubMed1985

Purification and partial characterization of megamodulin, a heat-stable protein factor from E. coli and its stimulatory effect on RNA polymerase holoenzyme.

Megamodulin, a heat-stable protein from Escherichia coli was isolated and purified near homogeneity as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis. It had a molecular weight of 71,000 and pl between 3.5 and 4.0. This factor stimulated E. coli RNA polymerase 71-fold in the presence of a synthetic template such as poly (rA).p(dT). When TATAAA sequence was used as template, the RNA polymerase activity was increased 68 times by this factor. The possible mechanism by which this protein factor may regulate the RNA polymerase activity has been described.

Amino Acids↗
PubMed1979

Changes in the activities of protein kinase modulators in the cerebellum of mice due to ethanol, caffeine, or phenobarbital administration.

Decreased activities of both the inhibitory modulator of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase (A-PK) as well as the stimulatory modulator of guanosine 3':5'-monophosphate (cGMP)-dependent protein kinase (G-PK) from the mouse cerebellum were noted due to the administration of excessive doses of ethanol, caffeine, and phenobarbital for up to 28 days. The dose-dependent of the inhibition of A-PK or the stimulation of G-PK was observed as a function of the amount of protein kinase modulators in the cerebellum of mice receiving different doses of ethanol.

Animals↗
PubMed1979

Ontogenetic changes in relative levels of cyclic AMP-dependent and cyclic GMP-dependent protein kinases in prostates, epididymides and testes from guinea-pigs.

Changes in relative levels of cyclic AMP-dependent protein kinase (A-PK) and cyclic GMP-dependent protein kinase (G-PK) in prostates, epidymides and testes from guinea-pigs were examined at 3 different ages. During postnatal development, a decrease in the ratio of the 2 classes of protein kinases was seen in prostates, whereas increases of the ratios of the enzymes were found in epididymides and testes.

Animals↗
PubMed1977

Cyclic GMP-dependent and cyclic AMP-dependent protein kinases, protein kinase modulators and phosphodiesterases in arteries and veins of dogs. Distribution and effects of arteriovenous fistula and arterial occlusion.

Possible involvement of cyclic GMP-dependent and cyclic AMP-dependent protein kinases, protein kinase modulators and cyclic nucleotide phosphodiesterases in functions of vascular tissues were investigated in the dog. All of the above activities, localized in the smooth muscle-rich inner layer of the blood vessels, were found to be higher in the arteries than in the veins. The peripheral arteries were disproportionately richer in cyclic GMP-dependent protein kinase (as indicated by high ratios of cyclic GMP-dependent to cyclic AMP-dependent protein kinase) than were the veins, with the exception of the pulmonary artery, an atypical arterial tissue exposed to low blood pressure. Interestingly, the protein kinase ratio for the aorta, an artery with no significant role in blood pressure regulation, was not higher than that for the vena cava. Creation of femoral arteriovenous fistulae in the dogs led to preferential reductions in the cyclic GMP-dependent enzyme activity both in the proximal and distal arteries, whereas it was elevated in the stressed vein distal to the anastomotic site. The cyclic GMP-dependent enzyme was preferentially reduced in the saphenous artery distal to occlusion. Changes in the cyclic GMP-dependent enzyme activity appeared to precede gross atrophy or hypertrophy of the vessels. It is suggested that the vascular cyclic GMP-dependent protein kinase may be closely related to peripheral resistance and its regulation.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1976

Isolation of stimulatory modulator of guanosine 3':5'-monophosphate-dependent protein kinase from mammalian heart devoid of inhibitory modulator of adenosine 3':5'-monophosphate-dependent protein kinase.

The stimulatory and inhibitory activities in the crude preparation of protein kinase modulator from dog heart were separated by Sephadex G-100 gel filtration, and the stimulatory modulator was further purified by DEAE-cellulose chromatography. The isolated stimulatory modulator, as the crude modulator preparation, stimulated the activity of the purified guanosine 3':5'-monophosphate (cGMP)-dependent protein kinases of both mammalian and arthropod origins in the presence of cGMP. The cGMP-dependent protein kinases were not activated by cGMP in the absence of either the isolated stimulatory modulator or the crude modulator. The stimulatory modulator, unlike the crude modulator had no effect on the activity of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase. The stimulatory modulator was a protein since its activity was destroyed by trypsin but was resistant to hydrolysis by DNase, RNase, phospholipase C, and lysozyme. The isolated inhibitory modulator, presumably the same as the protein inhibitor of cAMP-dependent protein kinase reported by Walsh et al. (Wash. D.A., Ashby, C.D., Gonzalez, C., Calkins, D., Fischer. E.H., and Krebs, E.G. (1971) J. Biol. Chem. 246, 1977-1985), depressed the cAMP-stimulated activity of cAMP-dependent protein kinase as did the crude preparation of protein kinase modulator. The isolated inhibitory modulator, unlike the crude preparation, was without effect on cGMP-dependent protein kinase. The present findings provide evidence to support that in mammals there are separate proteins for the stimulatory and the inhibitory activities of protein kinase modulator, in contrast to the modulator from an arthropod tissue (lobster tail muscle, Donnelly et al. (Donnelly, T.E., Jr., Kuo, J.F., Reyes, P.L., Liu, Y.P., and Greengard, P. (1973) J. Biol. Chem. 248, 190-198) which has been shown to possess both activities.

Animals↗