Table 1 AMP production as an indicator of the enzymatic activity of various forms of PRPS.

From: Arginylation regulates purine nucleotide biosynthesis by enhancing the activity of phosphoribosyl pyrophosphate synthase

Cells transfected with

AMP production (Ave±s.e.m.)

Remove AMP from endogenous PRPS (Ave±s.e.m.)

Normalized GFP fusion protein level (Ave±s.e.m.)

Normalized AMP specific from PRPS-GFP (Ave±s.e.m.)

M-PRPS2-GFP

12.6±1.8

9.1±1.8

1

9.1±1.8

R-PRPS2-GFP

24.6±5.9

21.2±5.9

0.67±0.1

31.6±5.9

Untransfected

3.5±0.6

N/A

N/A

N/A

  1. AMP, adenosine monophosphate; Ave, average; GFP, green fluorescent protein; PRPS, phosphoribosyl pyrophosphate synthase.
  2. HEK293T cell extracts containing recombinant GFP-fused constitutively non-arginylated(M-) or arginylated (R-) PRPS2 were used to perform the enzymatic assay in the presence of the reaction substrate RP5 and a potent human adenylate kinase inhibitor A(5′)P5(5′)A. The values of AMP specifically from GFP-fused PRPS were obtained by subtracting that from endogenous enzyme activity as in untransfected cells. The data were further normalized by the corresponding levels of the GFP-fused proteins in the samples (see Fig. 3c). Three measurements were performed for each sample (n=3) to calculate the average value and s.e.m.
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