ProteinsBy Emily Hodgson and Joshua Bower

Primary structure• The amino acid sequence

Secondary structure• Alpha helix

• Beta sheet

Tertiary structure• Folding of the protein

Quaternary structure• Multiple polypeptides

• e.g. collagen

ALBUMINALBUMIN

Properties

Functions

Hypoalbuminaemia

Hyperalbuminaemia

Normal values = 3.5 - 5.0 g/dL50% of protein contentNegatively chargedProduced in the liver only

Oncotic pressureTransport - hormones, bilirubin, free fatty acids, exogenous drugs, metals, ionspH bufferNegative acute phase proteinCompetitively binds Ca ions

Liver disease (cirrhosis)Nephrotic syndromeExcess loss in bowel (protein-losing enteropathy, e.g., Ménétrier's disease)Burns (plasma loss in the absence of skin barrier)Redistribution (hemodilution [as in pregnancy], increased vascular permeability or decreased lymphatic clearance)Acute disease statesProtein energy malabsorption

DehydrationHigh protein diet

Hypoalbuminaemia signs and symptoms

• Leukonychia

• Oedema and ascites (decreased oncotic pressure)

• Jaundice

• N.b. give lower doses of drugs as more will be free in plasm