Kinin
Encyclopedia
A kinin is any of various structurally related polypeptides, such as bradykinin
and kallikrein
. They are members of the autacoid family.
They act locally to induce vasodilation
and contraction of smooth muscle
.
It is a component of the kinin-kallikrein system
.
Their precursors are kininogen.
In botany
, plant hormone
s cytokinin
s were first called kinins, but the name was changed to avoid confusion.
Aspirin inhibits the activation of kallenogen by interfering with the formation of kallikrien enzyme
which is essential in the process of activation.
Bradykinin
Bradykinin is a peptide that causes blood vessels to dilate , and therefore causes blood pressure to lower. A class of drugs called ACE inhibitors, which are used to lower blood pressure, increase bradykinin further lowering blood pressure...
and kallikrein
Kallikrein
Kallikreins are a subgroup of serine proteases, enzymes capable of cleaving peptide bonds in proteins. In humans, plasma kallikrein has no known homologue, while tissue kallikrein-related peptidases encode a family of fifteen closely related serine proteases...
. They are members of the autacoid family.
They act locally to induce vasodilation
Vasodilation
Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
and contraction of smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
.
It is a component of the kinin-kallikrein system
Kinin-kallikrein system
The kinin-kallikrein system or simply kinin system is a poorly understood system of blood proteins that plays a role in inflammation, blood pressure control, coagulation and pain...
.
Their precursors are kininogen.
In botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
, plant hormone
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...
s cytokinin
Cytokinin
Cytokinins are a class of plant growth substances that promote cell division, or cytokinesis, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence...
s were first called kinins, but the name was changed to avoid confusion.
Aspirin inhibits the activation of kallenogen by interfering with the formation of kallikrien enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
which is essential in the process of activation.