Insulin diabetes treatment Flashcards
Pre-pro insulin
Sequence cut off
Insulin folded = disulphide bonds – 2 cystine residues, join A and B region
Storage of insulin
Hexamer stabilised by Zn2+ ions
Stable but not active
Types of insulin
Animal
Human - DNA technology
Analogues - altered human insulin
Insulin preparations
Short-acting: soluble, aspart, glulisine, lispro
Medium-acting: isophane
Long-acting: detemir, glargine
Size of insulin
Monomer > dimer > hexamer > aggregates
Humalin I
Contains protamine
Clustering of insulin, limiting diffusion
Humanlin S
No protamine
Protamine
Basic protein
Binds to negatively charged insulin and clusters insulin hexamers
Rapid-acting insulin
Insulin aspart: Proline to aspartate substitution in B chain
Insulin lispro: Two substitutions in B chain
Insulin glulisine: Two substitutions in B chain. Asparagine to lysine then glutamic acid
Long-acting insulin
Insulin glargine: Contains asparagine to glycine substitution in A chain. Two arginines added to carboxyl end of B chain. Less soluble
Insulin detemir: Covalently attached fatty acids, bind to albumin. Albumin and insulin compete for receptor, prolonging its action. Protects insulin from protease, increasing stability
Insulin degludec: Hexadecanedioc group added to B chain. Albumin binding multi-hexamers.
Injecting insulin
Orally ingested insulin degraded by protease
Subcutaneous
Stomach, buttocks, thighs
Rotated to avoid lipohypertrophy
<25C
Insulin pumps
Varied dose of rapid-acting insulin
Type 1 therapeutics
Islet cell transplantation
Cells injected through catheter in upper abdomen
Stem cell derived beta cells