Inhibits fibrillization of amyloid-beta peptide during the elongation phase. Has also been shown to assemble amyloid fibrils into protease-resistant aggregates. Binds heparin. Forms homodimers and homotrimers. Binds to the fibrillized forms of amyloid-beta protein 40 (beta-APP40) and amyloid-beta protein 42 (beta-APP42). Found associated with beta-APP42 more frequently than with beta-APP40. After proteolytic cleavage, CLAC is secreted. Expressed predominantly in brain. Deposited preferentially in primitive or neuritic amyloid plaques which are typical of Alzheimer disease. Undergoes proteolytic cleavage by furin protease to yield the soluble collagen-like Alzheimer amyloid plaque component. Glycosylated. Hydroxylated on 11% of proline residues and 49% of lysine residues. The disease is caused by variants affecting the gene represented in this entry. The pyrrolidone carboxylic acid reported in PubMed:11927537 probably formed artifactually from Glu-113 during the extraction procedure in 70% formic acid. In PubMed:15522881, the protein was found to have unblocked Glu at the N-terminus.