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Ling-Xin Chen

Publications and source records attributed to Ling-Xin Chen.

6 recordsLinked to original sources
PubMed2006

Interaction study between double-stranded DNA and berberine using capillary zone electrophoresis.

Two non-self-complementary 17-mer double-stranded DNA (dsDNA) with four different central base pairs were designed to systematically investigate the binding affinity and sequence specificity of berberine with dsDNA by capillary zone electrophoresis (CZE). The data analysis with the Kenndler model proved only low affinity between dsDNA and berberine and suggested some weak binding preference of berberine for AATT-containing to GGCC-containing dsDNA. The binding constant, Ka, between berberine and dsDNA(AB) was about (1.0 +/- 0.7) x 10(3) M(-1). In addition, the separation of single-stranded DNA (ssDNA) from dsDNA under simple electrophoretic conditions enabled CZE to be a potentially alternative tool to check the extent of DNA annealing, which is usually done by the time-consuming and labor-intensive slab electrophoresis.

Base Sequence↗
PubMed2005

[HPLC fingerprint for the Corydalis saxicola Bunting injection].

AIM: To establish the fingerprint of Corydalis saxicola Bunting injection. METHODS: It was performed by HPLC Kromasil column was used with acetonitrile and H2O as mobile phase. The flow rate was 0.5 mL x min(-1). The detection wavelength was 254 nm. The mass spectrometry detection was performed on a trap equipped with an ESI interface and operated in positive-ionization mode. RESULTS: Eleven components of Corydalis saxicola Bunting were identified by LC-MS and 7 of them were quantified. CONCLUSION: The fingerprint chromatogram could represent the characteristics of Corydalis saxicola Bunting injection. Evaluation of resemblances and results of precision were satisfactory. This method could be used as quality and quantity control.

Berberine↗
PubMed2003

Arf regulates interaction of GGA with mannose-6-phosphate receptor.

The role of ADP-ribosylation factor (Arf) in Golgi associated, gamma-adaptin homologous, Arf-interacting protein (GGA)-mediated membrane traffic was examined. GGA is a clathrin adaptor protein that binds Arf through its GAT domain and the mannose-6-phosphate receptor through its VHS domain. The GAT and VHS domains interacted such that Arf and mannose-6-phosphate receptor binding to GGA were mutually exclusive. In vivo, GGA bound membranes through either Arf or mannose-6-phosphate receptor. However, mannose-6-phosphate receptor excluded Arf from GGA-containing structures outside of the Golgi. These data are inconsistent with predictions based on the model for Arf's role in COPI veside coat function. We propose that Arf recruits GGA to a membrane and then, different from the current model, 'hands-off' GGA to mannose-6-phosphate receptor. GGA and mannose-6-phosphate receptor are then incorporated into a transport intermediate that excludes Arf.

ADP-Ribosylation Factors↗
PubMed2002

Arf1 dissociates from the clathrin adaptor GGA prior to being inactivated by Arf GTPase-activating proteins.

The effectors of monomeric GTP-binding proteins can influence interactions with GTPase-activating proteins (GAPs) in two ways. In one case, effector and GAP binding to the GTP-binding protein is mutually exclusive. In another case, the GTP-binding protein bound to an effector is the substrate for the GTPase-activating protein. Here predictions for these two mechanisms were tested for the Arf1 effector GGA and ASAP family Arf GAPs. GGA inhibited Arf GAP activity of ASAP1, AGAP1, ARAP1, and Arf GAP1 and inhibited binding of Arf1.GTPgammaS to AGAP1 with K(i) values correlating with the K(d) for the GGA.Arf1 complex. ASAP1 blocked Arf1.GTPgammaS binding to GGA with a K(i) similar to the K(d) for the ASAP.Arf1.GTPgammaS complex. No interaction of GGA with ASAP1 was detected. Consistent with GGA sequestering Arf from GAPs, overexpression of GGA slowed the rate of Arf dissociation from the Golgi apparatus following treatment with brefeldin A. Mutational analysis revealed the amino-terminal alpha-helix and switch I of Arf1 contributed to interaction with both GGA and GAPs. These data exclude the mechanism previously documented for Arf GAP1/coatomer in which Arf1 is inactivated in a tripartite complex. Instead, termination of Arf1 signals mediated through GGA require that Arf1.GTP dissociates from GGA prior to interaction with GAP and consequent hydrolysis of GTP.

3T3 Cells↗
PubMed2002

[Application of electroosmotic pump on micro column liquid chromatography].

An electroosmotic pump(EOP) was designed and evaluated, which could replace the mechanical pump. The EOP could generate 2.0 MPa-6.0 MPa output pressure and tens of nL/min-3 microL/min flow rate. A test mixture containing naphthalene, anthracene and phenanthrene was separated on a 14 cm x 320 microns i.d., 5 microns, C18 micro column with acetonitrile/water as a mobile phase, which demonstrated the applicability of the EOP.

Anthracenes↗