To find out if amyloids can behave like enzymes too, Korendovych and his team designed seven simple peptides that were made from seven amino acids.
Four of the seven peptides formed amyloids which had the ability to catalyse the hydrolysis of organic molecules called esters - a reaction that some enzymes catalyse too.
Our biosensor test uses a new molecular recognition tool that works like a lock that only fits one key; it picks out the ball-shaped amyloid clusters without detecting the individual amyloids.
The test provides an accurate diagnosis by identifying even small quantities of amyloid-beta clusters- the toxic proteins responsible for Alzheimer's disease- present in the blood stream, and differentiating them from the individual amyloid proteins found in healthy people.
(A[sz]) peptides are generated as cleavage products 39 to 43 amino acids in length from the membrane protein, Amyloid
Precursor Protein (APP) by two proteases, ?
The results are the first to suggest that toxic desmin amyloids
can form in response to stress placed on the heart.
We report 2 cases of laryngeal amyloidosis in which dense plasma cell infiltrates were found in the vicinity of the amyloid
deposits; in view of this finding, we suspected a hematologic disease--plasmacytoma in particular.
Many researchers hold that plaques consisting of an amyloid
known as beta-amyloid
kill brain cells and thereby cause Alzheimer's disease.
Amyloidosis in humans was first recognized in the mid-19th century when Rudolf Virchow coined the term amyloid
(for starch or cellulose) to describe abnormal extracellular material seen in the liver at autopsy.
These findings are significant because it is the first time a combination of specific chemicals has successfully destroyed diverse forms of amyloids
at the same time," Nature magazine quoted Dr Martin Duennwald of BBRI, who co-led the study with Dr.
This immunization, they found, generated antibodies that prevented the accumulation of beta-amyloid
within the mouse brain and even cleared existing amyloid
deposits, known as plaques.
This finding establishes for the first time a direct link between beta amyloid
and neuron destruction in live animals, says study coauthor Neil W.
plaques are lesions that form between brain neurons as protein fragments (beta-amyloids
) are snipped off.
Since completing the reported study, she and her co-workers have made genetic probes that distinguish between the two forms of amyloid
(with and without the built-in inhibitor), and have gotten what Neve calls "exciting" preliminary results on the distribution of different amyloids
Precursor Protein, APP, is predominantly processed by a-Secretase, producing a 83-amino acid C-terminal fragment, C83; while a small amount is processed by b-Secretase, producing a 99-amino acid C-terminal fragment, C99.