The Saccharomyces cerevisiae APE1 gene product, aminopeptidase I (API), is a soluble hydrolase that has been shown to be localized to the vacuole. API lacks a standard signal sequence and contains an unusual amino-terminal propeptide. We have examined the biosynthesis of API in order to elucidate the mechanism of its delivery to the vacuole. API is synthesized as an inactive precursor that is m...

Alcohol can be considered as a nutritional toxin when ingested in excess amounts and leads to skeletal muscle myopathy. We hypothesized that altered protease activities contribute to this phenomenon, and that differential effects on protease activities may occur when: (1) rats at different stages in their development are administered alcohol in vivo; (2) acute ethanol treatment is superimposed ...

A method is recommended for the measurement of the catalytic concentration of alanine aminopeptidase in the urine of man, rat, and dog, using L-alanine-4-nitroanilide as substrate. In currently used methods, substrate concentrations between 1.7 and 2.0 mmol/l are used. Kinetic experiments show, however, that the reaction is inhibited by substrate concentrations exceeding 0.8 (man), 0.3 (rat) an...

The experiment was carried out on 20 Swiss male mice divided into experimental (E, n=10) and control (C, n=10) group. E mice were intraperitoneally injected with glucagon (15 μg/kg b.w.) twice daily for eight days, while mice C with 250 μl 0.9% NaCl/mouse (to exclude the injection effect only). In the lysosomal fraction of the liver the activities of acid phosphatase, β-N-acetyl-hexosaminidase,...

We found a cysteine proteinase in lysosomes of rat liver with the remarkable properties to hydrolyze both aminopeptidase and endopeptidase substrates. The main proofs of the endoaminopeptidase nature of cathepsin H was the competitive inhibition of the enzyme activity by aminoand endopeptidase substrates among one another and the uniform inhibition or activation of the endopeptidase as well as ...

The stability to pH and denaturing agents of crystalline leutine aminopeptidase (bovine lens) (EC 3.4.1.1) is reported. The native enzyme exhibited a molecular weight of 327,000. In 7 M urea below pH 3 and in 23.7 M guanidinium chloride below pH 8.5, both leucine aminopeptidase and its reduced and carboxamidomethylated derivative exhibited a molecular weight on equilibrium centrifugation of 54,...

The activity of soil microbial extracellular enzymes is strongly controlled by temperature, yet the degree to which temperature sensitivity varies by microbe and enzyme type is unclear. Such information would allow soil microbial enzymes to be incorporated in a traits-based framework to improve prediction of ecosystem response to global change. If temperature sensitivity varies for specific soi...