RESUMO
Fruiting bodies of Phellinus linteus were extracted by hot water and alkali methods. Sugar contents of PL-H (hot water extract) and PL-A (alkali water extract) were 81.1%, 37.4% and protein contents were 6.2%, 21.8%, respectively. Amino acid pattern showed that two extracts contained large amount of aspartic acid and alanine. Two extracts showed characteristic IR absorption pattern for glycosidic bond at 890 cm(-1). PL-H was divided two fractions by gel filtration chromatography and the molecular weights of each fraction were estimated to be about 10 kD and 225 kD, respectively and also PL-A was estimated 10 kD. Two extracts showed strong antitumor, immunomodulating and antioxidant activities, and were compared with commercialized glycopeptide anticancer drugs.
RESUMO
A soluble Cr(VI) reductase was purified from the cytoplasm of Escherichia coli ATCC 33456. The molecular mass was estimated to be 84 and 42 kDa by gel filtration and SDS-polyacrylamide gel electrophoresis, respectively, indicating a dimeric structure. The pI was 4.66, and optimal enzyme activity was obtained at pH 6.5 and 37 degrees C. The most stable condition existed at pH 7.0. The purified enzyme used both NADPH and NADH as electron donors for Cr(VI) reduction, while NADPH was the better, conferring 61%; higher activity than NADH. The Km values for NADPH and NADH were determined to be 47.5 and 17.2 micromol, and the Vmax values 322.2 and 130.7 micromol Cr(VI) min(-1)mg(-1) protein, respectively. The activity was strongly inhibited by N-ethylmalemide, Ag2+, Cd2+, Hg2+, and Zn2+. The antibody against the enzyme showed no immunological cross reaction with those of other Cr(VI) reducing strains.
