The 1 equiv reaction between ascorbic acid and cytochrome b(561) is a good model for redox reactions between metalloproteins (electron carriers) and specific organic substrates (hydrogen-atom carriers). Diethyl pyrocarbonate inhibits the reaction of cytochrome b(561) with ascorbate by modifying a histidine residue in the ascorbate-binding site. Ferri/ferrocyanide can mediate reduction of DEPC-t...

bstract The article describes a simplified and efficient protocol for non-radioactive in situ hybridization experiments on tissue sections. The sensitivity of the method allows the expression of genes to be studied with transcript levels ranging from very low (20–30) to high (several thousands) copy numbers per cell. The immediate procession of cryosections to the ISH protocol after sectioning,...

RNA samples and ladders were prepared according to the protocols described in the instruction manuals for the Experion RNA analysis kits and the Agilent 6000 LabChip kits. RNA samples and ladders were first heat-denatured for 2 min at 70°C and then kept on ice until use. The heat-denatured total RNA and mRNA stocks were diluted to the desired final concentrations in either RNase-free TE buffer,...

D-Aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) was strongly inactivated by diethylpyrocarbonate (DEPC). An H67N mutant was barely active, with a kcat/Km 6.3 x 10(4) times lower than that of the recombinant wild-type enzyme, while the H67I mutant lost detectable activity. The H67N mutant had almost constant Km, but greatly decreased kcat. These results sug...

Intracellular microelectrode techniques and extracellular pH measurements were used to study the dependence of apical Na+/H+ exchange on mucosal and intracellular pH and on mucosal solution Na+ concentration ([Na+]o). When mucosal solution pH (pHo) was decreased in gallbladders bathed in Na(+)-containing solutions, aNai fell. The effect of pHo is consistent with titration of a single site with ...

BACKGROUND Interest is increasing in the role of peptide-bound amino acids (AAs) in milk protein synthesis because studies have found that the uptake of some essential AAs by the mammary gland cannot meet the requirements for milk protein synthesis. Although the role of dipeptides in milk protein synthesis is clearly established, little is known about the underlying mechanisms. OBJECTIVE The ...