Biosynthesis and enzymatic characterization of human SKI-1/S1P and the processing of its inhibitory prosegment.

Biochemical and enzymatic characterization of the novel human subtilase hSKI-1 was carried out in various cell lines. Within the endoplasmic reticulum of LoVo cells, proSKI-1 is converted to SKI-1 by processing of its prosegment into 26-, 24-, 14-, 10-, and 8-kDa products, some of which remain tightly associated with the enzyme. N-terminal sequencing and mass spectrometric analysis were used to map the cleavage sites of the most abundant fragments, which were confirmed by synthetic peptide processing.

Mouse plasma kallikrein: cDNA structure, enzyme characterization, and comparison of protein and mRNA levels among species.

There is differential regulation of liver mRNA levels of rat (r) and mouse (m) plasma kallikrein (PK), as observed on Northern blots. Affinity purification of mPK and rPK, microsequencing, and radioimmunoassay in either rat or mouse showed that the difference in mRNA levels does not appreciably affect the circulating PK concentration. Nuclear run-off assays demonstrated that the regulation of the mRNA level of PK is post-transcriptionally controlled.

Complete amino acid sequence of BSP-A3 from bovine seminal plasma. Homology to PDC-109 and to the collagen-binding domain of fibronectin.

Bovine seminal plasma was shown to contain three similar proteins, called BSP-A1, BSP-A2 and BSP-A3. Both BSP-A1 and BSP-A2 were shown to be molecular variants of a recently characterized peptide called PDC-109. They seem to differ only in their degree of glycosylation and otherwise seem to possess an identical amino acid composition.

Determination of methylated basic, 5-hydroxylysine, elastin crosslinks, other amino acids, and the amino sugars in proteins and tissues.

Analytical single-column chromatographic methods have been developed for determining all methylated basic amino acids, isodesmosine, desmosine, the amino sugars glucosamine and galactosamine, the diastereoisomers of 5-hydroxylysine, and related compounds at picomole levels in protein and tissue hydrolysates. Complete resolution of all these unique basic amino acids as discrete peaks was achieved in 5.4 on a 50 X 0.

beta 2-Inhibin contains the active core of human seminal plasma beta-inhibin: synthesis and bioactivity.

The complete synthesis of the C-terminal 28 residues segment 67-94 of human seminal plasma beta-Inhibin, called beta 2-Inhibin, is reported. The Inhibin-like activity of the native 94 amino acids beta-Inhibin is compared to that of the synthetic replica of beta 2-Inhibin. In all assays used both peptides effectively suppress the FSH release induced by LHRH but have little effect on the LH release.