Matured hop extract reduces body fat in healthy overweight humans: a randomized, double-blind, placebo-controlled parallel group study.

Background: Hops are the main components of beer that provide flavor and bitterness. Iso-α-acids, the bitter components of beer, have been reported to reduce body fat in humans, but the bitterness induced by effective doses of iso-α-acids precludes their acceptance as a nutrient. The matured hop bitter acids (MHBA) of oxidized hops appear to have a more pleasant bitterness compared to the sharper bitterness of iso-α-acids.

Conserved residues in membrane-bound acid pyrophosphatase from Sulfolobus tokodaii, a thermoacidophilic archaeon.

A membrane-intrinsic acid pyrophosphatase (ST2226) from Sulfolobus tokodaii, a thermoacidophilic archaeon, is possibly involved in glycoprotein biosynthesis and belongs to the phosphatidic acid phosphatase class 2 superfamily, including both membrane-intrinsic and soluble enzymes with divergent functions ranging from dephosphorylation of undecaprenylpyrophosphate and phospho-monoesters such as glucose-6-phosphate to vanadium-containing chloroperoxidation. ST2226 is an archaeal ortholog of these enzymes sharing a common phosphatase motif. Through site-directed mutagenesis as to each of the conserved residues, the catalytic roles of the latter were deduced, as well as the transmembrane topology with all the conserved residues in close proximity to the outside of the membrane.

Membrane-bound acid pyrophosphatase from Sulfolobus tokodaii, a thermoacidophilic archaeon: heterologous expression of the gene and characterization of the product.

Membranes of Sulfolobus tokodaii, a thermoacidophilic archaeon that grows optimally at pH 2-3, 75-80 degrees C, show the ability to hydrolyze PPi with an optimum pH of 2-3. This acid PPase is proposed to be a dolicholpyrophosphatase that participates in glycoprotein biosynthesis. In the present study, the archaeal membranes hydrolyzed isopentenylpyrophosphate and geranylpyrophosphate, compounds related to dolicholpyrophosphate, at pH 3.