cDNA cloning of a human 100 kDa de-ubiquitinating enzyme: the 100 kDa human de-ubiquitinase belongs to the ubiquitin C-terminal hydrolase family 2 (UCH2).

The full length cDNA encoding a 100 kDa human de-ubiquitinating enzyme, referred to as de-ubiquitinase was obtained using one clone selected from a randomly sequenced human brain cDNA library and specific primers. The sequence of 18 peptides generated from the de-ubiquitinase isolated from out-dated human erythrocytes matched perfectly with the predicted amino acid sequence, which would encode a protein containing 858 amino acids (calculated M(r) = 95,743 Da). Homology search disclosed that the protein is a member of a large family of ubiquitin C-terminal hydrolases (UCH2), that was defined on the basis of the presence of two specific patterns, 'the Cys- and His-domains', which are likely to be involved in the de-ubiquitinating activity [7].

A human de-ubiquitinating enzyme with both isopeptidase and peptidase activities in vitro.

Some enzymatic and physicochemical properties of a human ubiquitin-specific isopeptidase are reported. The enzyme was purified to homogeneity from red blood cells and its specificity towards polymeric ubiquitin substrates suggests a de-ubiquitinating activity capable of cleaving 'head-to-tail' polyUb chains as well as isoamide 'branched' Ub dimers. KM values show a 10 fold preference for the cleavage of branched Ub dimers over head-to-tail Ub dimers.

Secretion of an Mr 60000 protein by benomyl-treated cells of Neurospora crassa.

In the presence of the microtubule inhibitor benomyl at micron concentrations, cells of Neurospora crassa wild type strain St. Lawrence 74A were found to secrete high amounts of an Mr 60 000 protein into the culture medium (about 35 micrograms/ml after a 12 h treatment). The secretion also occurred after treatment with the other antitubulin drugs carbendazim (MBC), nocodazole, thiabendazole, and griseofulvin.