1. Series of colorimetric dynamic assays allowed the study of the inhibition of cholinesterases by F(-) ions in vitro, by using, as sources of enzyme, whole human blood, human serum, homogenized rat brain and two preparations of red blood cells (human and bovine) whose enzymic purity was ascertained. 2. The first evidence of inhibition of human serum pseudocholinesterase by fluoride was noticed...

As the first step in the study of the amino acid sequence of horse heart cytochrome c, it was essential to establish the exact composition of the protein. Although the molecular weight is low (approximately 12,000) (1) and the protein contains less than 110 amino acid residues per mole, analyses by three diierent laboratories (2-4) have not yielded strictly concordant results. These analyses ar...

Tryptic hydrolysis of galactosyltransferase purified from bovine milk by affinity chromatography resulted in a decrease in the amount of the high molecular weight form (58,000) with a concomitant increase in the amount of lower molecular weight form (42,000) with little loss of activity. After extensive activity loss, a peptide of molecular weight 38,000 remained as the predominant species and ...

Lysophosphatidylcholine at concentrations of 30 micromolar stimulated the rate of MgATP-dependent H(+)-accumulation in oat (Avena sativa L. cv Rhiannon) root plasma membrane vesicles about 85% while the passive permeability of H(+) was unchanged. Activation was dependent on chain length, degree of saturation, and head group of the lysophospholipid. A H(+)-ATPase assay was developed that allowed...

Evidence that indoleacetic acid (IAA) conjugates are metabolized via enzyme-catalyzed hydrolysis to free IAA and that their biological activities are related to the rates at which they are hydrolyzed by the tissue is presented. These conclusions are based on the following observations. Slow but continuous decarboxylation of the IAA moiety of IAA-l-alanine and IAA-glycine occurs when these conju...

We describe a new method of complete analysis for lecithin, lysolecithin, and sphingomyelin in amniotic fluid. The analysis is based on alkaline hydrolysis of the lecithins and the enzymic hydrolysis of sphingomyelin. The choline formed in each instance is enzymically phosphorylated with [gamma-32P]ATP to yield [gamma-32P]phosphorylcholine, which is isolated by anion-exchange chromatography and...

The intranuclear distribution of newly replicated DNA and of the proliferating cell nuclear antigen (PCNA) was mapped by confocal laser scanning microscopy after simultaneous immunofluorescent labelling of incorporated bromodeoxyuridine (BrdUrd) and PCNA. A mild hydrolysis with HCl followed by an enzymic digestion of DNA was used to produce single-stranded DNA required for BrdUrd immunorevelati...

A monosialosyl ganglioside, sialosylpentaglycosyl-ceramide, has been isolated from chicken pectoral muscle. This ganglioside is the first to be found which contains the glycosphingolipid structure of the globo series. It was extracted from tissue with a mixture of tetrahydrofuran and aqueous KCl and purified by anion exchange and silicic acid chromatography. Enzymic hydrolysis utilizing specifi...

Three enzymic phenomena, inactivation by oxygen, Q(OO2) measurements of a dehydrogenase system, and hydrolysis of acetyl phosphate by a phosphatase of Clostridium kluyveri, were studied by means of the differential microrespirometer. Respiration of yeast cells was also measured with the same instrument. All results obtained in the four types of study agreed closely with earlier results obtained...

A highly sensitive fluorimetric assay for the measurement of pyridoxal and pyridoxal phosphate in biological tissues is described. The method involves the enzymic hydrolysis of pyridoxal phosphate to pyridoxal. The pyridoxal (free or total) is separated on an anion-exchange column, concentrated by cation-exchange chromatography and reacted with potassium cyanide under slightly alkaline conditio...