ATP Sulfurylase from; Penicillium chrysogenum:; Is the Internal Level of the Enzyme Sufficient to Account for the Rate of Sulfate Utilization? Journal Article uri icon

Overview

abstract

  • ; The in vivo rate of sulfate activation in; Penicillium chrysogenum; (wild-type strain ATCC 24791) was determined to be 0.19 ± 0.09 μmol g; −1; (dry weight) min; −1; by the following methods. (i) The maximum growth of the organism in synthetic medium was a linear function of the initial Na; 2; SO; 4; concentration between 0 and 8 × 10; −4; Na; 2; SO; 4; . The growth yield was 1.64 × 10; −2; g (dry weight) of mycelium per μmol of added sulfate, corresponding to a minimum sulfur requirement of 61 μmol/g (dry weight). Under these conditions (limiting sulfate) the minimum doubling time of; P. chrysogenum; in submerged culture was about 3.8 h, corresponding to a maximum exponential growth rate constant of 3.0 × 10; −3; min; −1; . If all the sulfur in this mycelium passed through adenosine-5′-phosphosulfate, the rate of sulfate activation in vivo must have been 0.183 μmol min; −1; g; −1; (dry weight). (ii) In the presence of excess; 35; SO; 4; 2−; , the total organic; 35; S produced varied with the mycelial growth rate. However, until the culture approached maximum density, the product of [(growth rate constant) × (organic; 35; S content)] was nearly constant at 0.24 to 0.28 μmol min; −1; g; −1; (dry weight). (iii) A sulfur-starved mycelium pulsed with 10; −4; M; 35; SO; 4; 2−; produced organic; 35; S at a rate of about 0.10 μmol min; −1; g; −1; (dry weight) under conditions where the internal concentrations of ATP and sulfate would permit ATP sulfurylase to operate at about 70% of its; ; V; max; ; . Cell-free extracts of; P. chrysogenum; growing rapidly on excess sulfate contained 0.22 U of ATP sulfurylase per g (dry weight). Thus, in spite of the relatively low specific activity of homogeneous ATP sulfurylase (0.13 U/mg of protein, corresponding to an active site turnover of 7.15 min; −1; ), the mycelial content of the enzyme was sufficient to account for the observed growth rate of the organism on inorganic sulfate as the sole sulfur source.;

publication date

  • January 1, 1979

Date in CU Experts

  • February 2, 2021 7:01 AM

Full Author List

  • Farley JR; Mayer S; Chandler CJ; Segel IH

author count

  • 4

Other Profiles

International Standard Serial Number (ISSN)

  • 0021-9193

Electronic International Standard Serial Number (EISSN)

  • 1098-5530

Additional Document Info

start page

  • 350

end page

  • 356

volume

  • 137

issue

  • 1