Chymotrypsinogen is a crystalline protein, which has been isolated from acid extracts of fresh cattle pancress by Kunitz and Northrop (1). This protein is transformed by minute amounts of trypsin into an active proteolytic enzyme, originally called chymotrypein (1), but later designated a-chymotrypsin by Kunitz (2). This paper deals with the determination of the sulfur amino acids and of tyrosi...

Two pools of plant-derived C31 n-alkane occurring respectively as free and humin-bound forms in the same soil have been distinguished by C/C analyses. The results show that the humin-bound molecule is on the average 7 years older than the free molecule. These findings indicate that apolar organic substances can be trapped temporarily into the soil matrix by weak forces. Dans un même sol, la ten...

In this work, the retention of cobalt on a humin (HU) derived from a brown coal is studied. Through a systematic and coordinated investigation of the behavior of the metal ions in solution (speciation diagrams as a function of pH) and their adsorption and precipitation processes with reactive functional groups of the solid (sorption isotherms), the interactions of different Co(II) species with ...

Radiocarbon dating was performed for the extracted organic fractions (cellulose-rich and humic acid fractions of plant fragment; fulvic acid, humic acid and humin fractions of humus substance) and shell from core sediments of the Erhai Lake, SW China. The 14C dating results reveal that there are considerable differences, but there apparently is a humic acid ≤ humin < fulvic acid fraction sequen...

The Cu(II) binding properties of Canadian Sphagnum peat moss, humic acid and humin extracted from the peat moss were investigated. Batch pH profile experiments indicated that the adsorption of Cu(II) is pH dependent. At pH 4.0 and 5.0 about 99% of the Cu(II) was bound by all three biomasses. Time-dependent experiments showed that the binding of Cu(II) is very rapid. The Cu(II) binding capacitie...

Observing changes in soil organic matter (SOM) is a fundamental part of defining the carbon cycle in natural and cultivated environments. However, relying on changes in the mass of soil C over short periods often produces conflicting results because of errors associated with sampling and analysis. In addition, C mass balance studies provide little interpretation of processes or turnover of spec...

Microcosm data were used to develop a deterministic model to describe how rhizodeposition affects the fate of phenanthrene in aged contaminated soil. Microbial mineralization and soil sequestration of 14C-phenanthrene were compared in microcosms amended weekly with phenolic-rich mulberry root extracts versus unamended controls. Mineralization was higher in the amended soils simulating the rhizo...