Lecture 38 Flashcards
(9 cards)
There are two isoforms of COX (1 and 2.) COX 1 is ______ active, whereas COX 2 is ______ (usually by trauma or inflammatory response) and is present in immuno-competent cells. COX 2 is inhibited by _____, whereas COX 1 is not.
CONSTITUTIVE
INDUCIBLE
Steroids
BOTH COX enzymes have 2 activities: First _______ and 2nd ______ to form PGH2 from arachidonic acid.
CYCLIZATION and PEROXIDATION
____ is the protaglandin involved with development, regulation, and activity of many immune cells. It is also involved in inducing _____ contractions during labor.
PGE2
Uterine
_____ has the opposite effect of Thromboxanes (which cause constriction and clotting of platelets) in areas where blood clots should not be forming. Essentially, it has a protective role against clotting.
PGI2
Aspirin works by blocking both COX enzymes. The ____ group of Aspirin binds to ____ on the COX enzymes, preventing ______ from entering the active site. Aspirin _____ (reversibly or irreversibly?) inhibits both COX enzymes, but it has a ____ (long or short?) half-life, so it’ll reduce but not abolish the ability of blood to clot bc new platelets are constantly being made.
ACETYL
SERINE
Arachidonic acid
Irreversibly
Short
Prostaglandins are not exactly hormones, but they do have an autocrine or ______ action (on nearby cells.)
Paracrine
Different from PGs, thromboxanes don’t have a ____-membered ring, and Leukotrienes (which are mediators of _____ and allergy) don’t have any ring structures.
5-membered
Asthma
______ A2 releases arachidonic acid from cell membranes, so then it can be acted on by the COX enzymes to produce ____.
Phospholipase A2
PGH2
COX 1 and COX 2 differ at position 523 in their active sites. COX 1 has an _____ in that amino acid position, while COX 2 has _____. This allows for COX 2 specific drug action (e.g. VIOX and Celebrex).
Isoleucine
Valine
