Creative Enzymes is specialized in measuring enzyme activities. With years of testing various enzymes and discovering new methods, Creative Enzymes has accumulated extensive experiences, which enable activity assay services of utmost quality. Among all enzyme testing services, activity determination of sulfate adenylyltransferase is one of the most popular ones.

Sulfate adenylyltransferase (EC 2.7.7.4) is an enzyme that catalyzes the transfer of the adenylyl group from ATP to inorganic sulfate, forming adenosine 5’-phosphosulfate (APS) and pyrophosphate (PPi). This reaction yields a high-energy phosphoric-sulfuric acid anhydride bond that drives the sulfur assimilatory pathway. Sulfate adenylyltransferase is widely distributed in nature and has been found in virtually all types of organisms. However, its physiological roles differ in organisms depending on their metabolic lifestyles. In many eukaryotes and bacteria, sulfate adenylyltransferase acts as the first enzyme in a cascade of proteins that activate inorganic sulfate (SO₄^2-) and incorporate it into organic compounds. APS produced by sulfate adenylyltransferase is subsequently phosphorylated at its 3’-position, yielding 3’-phosphoadenosine 5’-phosphosulfate (PAPS). In most plant and microbial cells, sulfate adenylyltransferase and APS kinase are isolate proteins. However, animals and some bacteria own a “PAPS synthetase” in which the activities of these two sulfate activating enzymes are co-located on a single polypeptide chain.

Sulfate adenylyltransferase plays a pivotal role in nature. First, in fungi, yeasts, most heterotrophic bacteria, algae, and higher plants, this enzyme catalyzes the first intracellular reaction in the reductive assimilation of inorganic sulfate into organic molecules (e.g., cysteine, methionine). Secondly, sulfate adenylyltransferase forms APS solely to serve as the terminal electron acceptor of heterotrophic metabolism in anaerobic sulfate reducing bacteria (e.g., Desulfovibrio). Thirdly, sulfate adenylyltransferase catalyzes the final reaction in the oxidation of reduced inorganic sulfur compounds to sulfate in certain chemo and photolithotrophic bacteria (e.g., Aquifex, Thiobacillus). Therefore, it is noteworthy that sulfate adenylyltransferase are receiving more and more attention due to its multiple, significant functions.

Figure: The crystal structure of sulfate adenylyltransferase from Saccharomyces cerevisiae.
PDB: 1G8F

Creative Enzymes is capable of performing the reliable enzymatic assay for sulfate adenylyltransferase rapidly and precisely. The activity of sulfate adenylyltransferase is measured by the continuous spectrophotometric assay using a lactate dehydrogenase-pyruvate kinase coupled method. It measures the product by coupling their formation to the oxidation of NADH in the presence of phosphoenolpyruvate, pyruvate kinase, lactate dehydrogenase, and NADH. The decrease in absorbance at 340 nm is monitored spectrophotometrically. Note that the enzymatic assays of Creative Enzymes are the most trusted and proven in the global market, resulting in quality services with a high rate of repeat sales. Ultimately, Creative Enzymes is honored for being your most trusty-worthy partner.