

Re: [IP] Why Humalog is so fast

Thanks Mary Jean, but like all good science, one answer just leads to
another question :-)   Now I'm wondering why they need the zinc there at
all.  Years ago I used to take Protomine Zinc insulin which was one of the
original long acting isulins.  I didn't realized zinc was in with R, too.
>From what you wrote, it would seem that if there were no zinc, then the R
would be just as rapidly absorbed as H.  So who knows why the insulin is
packaged with zinc?

<<<<<<<<<<From: email @ redacted
In a message dated 6/24/98 10:23:15 AM Mountain Daylight Time,
email @ redacted writes:

<< My question I guess was perhaps a bit more scientific, i.e., what
 is it about H that makes it diffuse more rapidly that R?  >>


OK, I was partially right earlier (and so were you).  I dug up the article I
was thinking of and have copied the pertinent portion below.  It is from the
ADA Forecast article entitled "at the controls with lispro" from the Nov. 97
issue.  It can be found on their website.


In the vial, human Regular insulin molecules exist as hexamers--six molecules
of insulin are bound together with zinc. This delays their absorption.

Insulin is a protein, and proteins are made up of amino acids. Lispro is
similar to human Regular insulin except that two amino acids, lysine and
proline (in positions 28 and 29 on the beta chain of insulin), are reversed in
order. As a result, molecules of lispro bind only weakly with each other. In a
vial of lispro, some insulin molecules cling to one another, but they come
apart very quickly after injection. Therefore, lispro is absorbed more quickly
than Regular. >>>>>>>>>>>>>>>>

Wayne Mitzner
Department of Environmental Health Sciences
The Johns Hopkins School of Hygiene and Public Health
615 N. Wolfe St.
Baltimore, MD 21205
Tel. 410 614 5446
Fax 410 955 0299

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