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Biomedical subjects

F L Huang

Publications and source records attributed to F L Huang.

121 records · Page 7Linked to original sources
PubMed1976

Separation and characterization of two phosphorylase phosphatase inhibitors from rabbit skeletal muscle.

Two heat-stable and trypsin-labile inhibitors of phosphorylase phosphatase, designated inhibitor-1 and inhibitor-2, were partially purified from extracts of rabbit skeletal muscle by heating and coloumn chromatography using DEAE-dellulose and Bio-gel P-60. Inhibitor-1 exists in an active phosphorylated form and an inactive dephosphorylated form. The interconversion of phosphorylated inhibitor-1 and dephosphorylated inhibitor-1 is mediated by protein kinase dependent on adenosine 3':5'-monophosphate (cyclic AMP) and a Mn2+-stimulated phosphoprotein phosphatase. Inhibitory activity of inhibitor-2 is not influenced by treatment with either the kinase or the Mn2+-stimulated phosphatase. The molecular weights of inhibitor-1 and inhibitor-2 estimated by sodium dodecylsulfate-polyacrylamide gel electrophoresis are 26000 and 33000 respectively. Both inhibitor-1 and inhibitor-2 inhibit phosphorylase phosphatase by a mechanism which appears to be non-competitive with respect to the substrate phosphorylase a. Inhibitor fractions at early stages of purification also inhibit cyclic-AMP-dependent histone phosphorylation, but this kinase inhibitory activity resides with a protein moiety which is separable from inhibitor-1 and inhibitor-2.

Adenine Nucleotides↗
PubMed1975

Inactivation of rabbit muscle phosphorylase phosphatase by cyclic AMP-dependent kinas.

Partially purified rabbit skeletal muscle phosphorylase phosphatase (EC 3.1.3.17; phosphoprotein phosphohydrolase) was inactivated when it was incubated with exogenous cyclic AMP-dependent protein kinase (EC 2.7.1.37; ATP:protein phosphotransferase), cyclic AMP, and ATP-Mg. Subsequent separation of the phosphatase by acrylamide gel electrophoresis or sucrose density centrifugation resulted in reactivation of the enzyme. The phosphatase decreased in molecular weight from approximately 70,000 to 52,000, and a phosphorylated inhibitor with molecular weight of 26,000 was found. Reactivation of phosphatase also occurred when it was incubated with MnCl2 or trypsin. The inhibitor was effective at less than 10(-8) M and was relatively heat stable. Its activity was destroyed by tryptic digestion and by dephosphorylation by a Mn-stimulated phosphatase. These observations support the possibility that phosphorylase phosphatase activity is controlled by cyclic AMP-dependent protein kinase and a Mn-stimulated phosphatase by a reaction involving phosphorylation and dephosphorylation of a protein phosphatase inhibitor.

Animals↗
PubMedDate not supplied

Studies on the structure and function of the carp gonadotropin alpha subunit by site-directed mutagenesis.

There are two genes encoding the alpha subunit of carp gonadotropin (alpha 1 and alpha 2 subunits). Our previous data have demonstrated that both alpha 1 and alpha 2 subunits expressed in insect cells are able to associate with the beta subunit, but only the alpha 1/beta heterodimer displays biological activity. In the mature protein, there are only four amino-acid residues different between the alpha 1 and alpha 2 subunits. In this study we used site-directed mutagenesis and expressed different mutant alpha subunits in insect cells to identify which residue might be important for biological activity of the alpha subunit. Our results suggested that the change of Arg-71 to Gln-71 affected the activity of the carp gonadotropin alpha subunit.

Amino Acid Sequence↗
PubMedDate not supplied

Bone mineral content in growing children.

In order to establish the normal values of bone mineral content (BMC) (g/cm2), the BMC of 140 healthy growing children including 49 girls (aged 5 to 16 years) and 91 boys (aged 7 to 17 years) was measured using Dual Photon absorptiometry (DPA) at L2-L4 level of the spine. The BMC increased significantly with age, after stratification by age. Both male and female children aged 7 to 10 years had similar BMC, but female children had significantly higher BMC at 12 to 13 years of age. We also established regression equations. Female: BMC = 0.38 + 0.021 x age. Male: BMC = 0.45 + 0.017 x age. They may be useful in estimating BMC in unknown individuals

Adolescent↗