The transcriptional factor GATA-6 gene produces two translational isoforms from a single mRNA through ribosomal leaky scanning. L-type GATA-6 has an extension of 146 amino acid residues at its amino terminus. In the e...The transcriptional factor GATA-6 gene produces two translational isoforms from a single mRNA through ribosomal leaky scanning. L-type GATA-6 has an extension of 146 amino acid residues at its amino terminus. In the extension, there is a unique PEST sequence (Glu31-Cys46), which is composed of an amino terminal Pro-rich segment and a carboxyl terminal Ser-cluster. Substitution of either half of the PEST sequence with Ala residues by cassette mutagenesis reduced the apparent molecular size of L-type GATA-6 on SDS-polyacrylamide gel-electrophoresis. However, the effect of substitution of the Pro-rich segment was much more significant;the mobility increase of the Pro-rich segment on the gel was 13% while that of the Ser-cluster was 8%. Substitution of each amino acid residue demonstrated that the effect of Pro substitution is greater than that of the Ser and Thr residues. Such increased mobility of L-type GATA-6 in the presence of a detergent may apparently correlate with the decrease in transcription activity in vivo as determined by means of luciferase reporter gene assay. The activity of ΔAla (with Ala residues instead of the PEST sequence) was reduced to one fifth of that of ΔA (with the PEST sequence). These results suggest that the PEST sequence of L-type GATA-6 does not function as a constitutive protein degradation signal, but rather plays structural and functional roles in the activation of gene expression on the GATA responsive promoter.展开更多
Heart failure (HF) incidence could cause further complications to other body organs, which might sometimes be fatal, and is accompanied by various biochemical alterations i.e. enzymatic changes. The objective of this ...Heart failure (HF) incidence could cause further complications to other body organs, which might sometimes be fatal, and is accompanied by various biochemical alterations i.e. enzymatic changes. The objective of this study was to measure the activity of gamma glutamyl transferase (GGT) as an early diagnostic indicator for HF patients;and to isolate the iso-enzymes for the purpose of finding the Michaelis-Menten constant (Km) and the maximum velocity Vmax of each iso-enzymes which enable follow up the development of HF disease. Samples of blood sera were collected from 120 patients of both genders (70 males and 50 female, aged 30 - 38 years old). Partial purification of iso-enzyme GGT was performed by precipitation, gel filtration, and ion exchange of the two iso-enzyme (I and II). The purity of the enzyme was confirmed by using Sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) into two clear bands. The results were compared with other 80 samples of healthy volunteers whose ages ranged between 25 - 78 years old, used as control. There has been a significant increase (p ≤ 0.01) in the activity of the enzyme GGT in the heart failure patient (66.9 ± 1.7 IU/L) in comparison with control (12.07 ± 0.60 IU/L). It is concluded that measurements of the iso-enzyme GGT could well benefit as a clear indicator criteria in prognosis of heart failure.展开更多
A specific reagent DACM [N-( 7-Dimethylamino-4-methyl-3-coumarinyl) maleimide] is used to study the -SH groups in lens proteins of normal and galactose cataractous rats. DACM when reacts readily with -SH groups form s...A specific reagent DACM [N-( 7-Dimethylamino-4-methyl-3-coumarinyl) maleimide] is used to study the -SH groups in lens proteins of normal and galactose cataractous rats. DACM when reacts readily with -SH groups form strong fluorescent adducts. The two -dimensional electrophoresis with DACM pre-labeled proteins is a simple and sensitive method for detecting -SH groups of protein subunit. In the present study, based on IEF/SDS-PAGE electrophoretically characterized soluble crystallins, describes specific ...展开更多
文摘The transcriptional factor GATA-6 gene produces two translational isoforms from a single mRNA through ribosomal leaky scanning. L-type GATA-6 has an extension of 146 amino acid residues at its amino terminus. In the extension, there is a unique PEST sequence (Glu31-Cys46), which is composed of an amino terminal Pro-rich segment and a carboxyl terminal Ser-cluster. Substitution of either half of the PEST sequence with Ala residues by cassette mutagenesis reduced the apparent molecular size of L-type GATA-6 on SDS-polyacrylamide gel-electrophoresis. However, the effect of substitution of the Pro-rich segment was much more significant;the mobility increase of the Pro-rich segment on the gel was 13% while that of the Ser-cluster was 8%. Substitution of each amino acid residue demonstrated that the effect of Pro substitution is greater than that of the Ser and Thr residues. Such increased mobility of L-type GATA-6 in the presence of a detergent may apparently correlate with the decrease in transcription activity in vivo as determined by means of luciferase reporter gene assay. The activity of ΔAla (with Ala residues instead of the PEST sequence) was reduced to one fifth of that of ΔA (with the PEST sequence). These results suggest that the PEST sequence of L-type GATA-6 does not function as a constitutive protein degradation signal, but rather plays structural and functional roles in the activation of gene expression on the GATA responsive promoter.
文摘Heart failure (HF) incidence could cause further complications to other body organs, which might sometimes be fatal, and is accompanied by various biochemical alterations i.e. enzymatic changes. The objective of this study was to measure the activity of gamma glutamyl transferase (GGT) as an early diagnostic indicator for HF patients;and to isolate the iso-enzymes for the purpose of finding the Michaelis-Menten constant (Km) and the maximum velocity Vmax of each iso-enzymes which enable follow up the development of HF disease. Samples of blood sera were collected from 120 patients of both genders (70 males and 50 female, aged 30 - 38 years old). Partial purification of iso-enzyme GGT was performed by precipitation, gel filtration, and ion exchange of the two iso-enzyme (I and II). The purity of the enzyme was confirmed by using Sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) into two clear bands. The results were compared with other 80 samples of healthy volunteers whose ages ranged between 25 - 78 years old, used as control. There has been a significant increase (p ≤ 0.01) in the activity of the enzyme GGT in the heart failure patient (66.9 ± 1.7 IU/L) in comparison with control (12.07 ± 0.60 IU/L). It is concluded that measurements of the iso-enzyme GGT could well benefit as a clear indicator criteria in prognosis of heart failure.
文摘A specific reagent DACM [N-( 7-Dimethylamino-4-methyl-3-coumarinyl) maleimide] is used to study the -SH groups in lens proteins of normal and galactose cataractous rats. DACM when reacts readily with -SH groups form strong fluorescent adducts. The two -dimensional electrophoresis with DACM pre-labeled proteins is a simple and sensitive method for detecting -SH groups of protein subunit. In the present study, based on IEF/SDS-PAGE electrophoretically characterized soluble crystallins, describes specific ...
