Molecular cloning and sequencing of a human cDNA encoding ornithine decarboxylase antizyme.

We report the cloning of a cDNA encoding the human homolog of ornithine decarboxylase antizyme from a human gingival fibroblast cDNA library. The human antizyme is 84% identical to the rat sequence and shows almost no homology to the E. coli antizyme.

Mechanistic features associated with induction of metalloproteinases in human gingival fibroblasts by interleukin-1.

Human gingival fibroblasts were treated with recombinant interleukin-1 (IL-1) to determine the effect of this stimulus on the relative expression of collagenase (MMP-1), stromelysin (MMP-3) and plasminogen activator (PA) mRNA. The steady-state mRNA levels for these genes were determined on Northern blots. IL-1 induced steady-state levels of these mRNAs to different extents.

Regulation of dipeptidyl aminopeptidase I and angiotensin converting enzyme activities in cultured murine brain cells by cortisol and thyroid hormone.

Cultures of dissociated brain cells from 15-day-old fetal mice were grown in the presence and absence of 20 or 50 nM triiodothyronine (T3), 30 or 300 nM cortisol, and 30 nM cortisol plus 50 nM T3 added to chemically defined media or in media supplemented with 15% serum from control and hypothyroid calves. The specific activities of five lysosomal enzymes--N-acetyl galactosaminidase, beta-glucuronidase, beta-galactosidase, cathepsin B, and dipeptidyl aminopeptidase I (DAP-I)--were higher in cells grown in calf serum than in cells grown in defined media. Of these enzymes, only DAP-I was elevated in activity when the cells were grown in hypothyroid calf serum instead of control calf serum.

Biosynthesis in vitro of sialosylgalactosyldiacylglycerol by mouse brain microsomes.

A sialyltransferase enzyme, present in the microsomal fraction of mouse brain, catalyzes the synthesis in vitro of a lipid, characterized as 1,2-diacyl-3-beta-D-galactosyl (3 comes from 2 N-acetylneuraminosyl)-sn-glycerol, (sialosylgalactosyldiacylglycerol) from 1,2-diacyl-3-beta-D-galactosyl-sn-glycerol (galactosyldiacylglycerol) and cytidine-5'-monophospho-N-acetylneuraminic acid (CMP-NeuNAc). The enzymatic activity increases proportionally, over a given range, with increasing concentrations of both substrates and of enzyme. The apparent Km of the enzyme for galactosyldiacylglycerol is 130 microM, and for CMP-NeuNAc, 780 microM.

Positional distribution of fatty acids in the glycerophospholipids of Tetrahymena pyriformis.

The positional distributions of the fatty acids in the major glycerophospholipids of Tetrahymena pyriformis W were analyzed. A comparison was made of the acyl distributions in normal and ergosterol-grown cells. It was assumed that the positional arrangement of fatty acids would serve as an indicator of acyltransferase enzyme specificity.