Conversations from the Hall of Fame

Sigmund Schwimmer, plant scientist, interviewed 2005

(Time: ~15:15 minutes)

My name is Sigmund Schwimmer. My official title is chief research biochemist emeritus collaborator with the United States Department of Agriculture, Agricultural Research Service of the United States Department of Agriculture.

April 27, 2006 I will have been associated with the Department of Agriculture for 70 years. 

I was born in Cleveland Ohio and went to Glenville High School and I got interested in science my junior high and every science course I took 'oh I'm going to be that kind of scientist'. Well, it just turns out in my senior year I took chemistry so I ended up being interested in chemistry and at that time to get a civil service job you had to take an assembled examination and there was an assembled examination in Cleveland, Ohio and being a wiz at chemistry it was just like another high school exam and I did very well except I got 97%. I did not know the atomic weight of barium. They asked what is the percentage of barium in barium sulfate and that's the one thing I didn't know and ever since then I know the atomic weight of barium is 137 and I'll know that to my dying day. 

In the fall, I started at Ohio State University and I stayed there until the spring, April 27. The New Deal then was trying to put the young people to work. The people who didn't go to college went to CCC, Civilian Conservation Corps and they went on the farms and forests and they did the sort of thing you do there. Where as NYA, National Youth Administration, were people who went to college and I was so thrilled to actually work in a research laboratory very exciting in those days. I got this wonderful telegram saying you have been appointed minor laboratory dish washer or something like that at the Department of Agriculture at the magnificent sum of 1020 per annum and of course I immediately accepted and I took my first trip, I think my first trip out of the city of Cleveland except for Columbus of course. 

And took a train down to Washington DC first thing they put me to do, job to do besides washing dishes was to run kjeldahls, micro-kjeldahls, determine the amount of nitrogen in proteins of the enzymes they were working on. Oh I should say I was appointed to a relatively newly formed in enzyme research laboratory and it turns out in 1926 they finally found out that most enzymes are made of proteins and there was a fellow by the name of Brown, C.A. Brown, one of the administrators said we got to get in on this new research on enzymes we're going to set up an enzyme research laboratory and they got a fellow who was traipsing around Europe he'd gotten his PhD at Colombia and he got another PhD at the University of Prague, I think it was, his name was Arnold Kent Balls and he became the first head of the enzyme research laboratory. I worked for Theodore Swenson who worked for Arnold Kent Balls and Theodore Swenson was the first director of the Western Regional Research Center.

Plant Enzyme Research 

I became interested in anything that had to do with enzymes particularly and in those days at the beginning I was the first one to large isolate enzymes from plants except for the regional isolation was from jack bean, urase from jack bean. 

So I worked on enzymes from sweet potatoes and I was kind of and also we also worked with an enzyme him that chops down proteins called papain and I was involved in that. As an assistant you understand, besides washing dishes and running these protein determinations I was actually involved in trying to figure out how to purify these things and then I was put on to the job of isolating enzymes from just starch and I was involved with crystalizing sweet potato beta-amylase and I more or less single handedly isolated the amylase used in making beer, alpha-amylase of malt barley.

 In that isolation I used a completely new principal in enzyme isolation which became very, very important later on and called biospecific affinity chromatography which means that the enzyme actually works, actually gets stuck to the substance it's going to work on but it doesn't chop it down it just is stuck so then you can pour amylase through it will get rid of everything else except the enzyme which will be stuck in this case would be stuck on to starch granules and then we worked out a way of getting a lutein that is separating the enzyme which called alpha-amlyase from the starch and from there it was a clear chute to purifying it was almost all pure from then on in.

Enzymes and Frozen Foods 

During the war they were interested in preserving foods and especially they wanted to push ahead frozen foods and frozen foods when stored for a long time will develop an off flavor if they are not first heated now you want to heat them to the shortest period of time possible and it was decided then that the reason these frozen foods developed off flavors is because the enzymes were working even in a frozen state and sort of little micro droplets present in the food. So if you first heat, so called blanch your vegetables or fruit you will be able to get rid of these enzymes. 

Now what enzymes should we use? Well the most stable enzymes known at that time was something called peroxidase and they were having problems. They would heat the vegetable and they test for the presence of this peroxidase enzyme and it wasn't there. They come back ten minutes later it was there. It suddenly was there. Their own tests. So what is the mechanism by which this enzyme comes back to life so to speak and that was my PhD thesis, developing the conditions and the rate at which the peroxidase is regenerated and I predicted that at that time that there must be something else going along to help regenerate, to guide, this protein which has been more messed up, you protein is a beautiful shape like an architectural marvel when its heated it gets to be like a mess of balled yarn and somehow or other it comes back and I said there must be something there, in my PhD thesis any ways, they wouldn't let me say this in my original paper, that must be helping to guide and fifty years later they now have something called, they now have the discovered something called chaperones which chaperone the protein back or heat shock proteins first they were called heat stock proteins now they are called chaperones and they chaperone so the kinky things don't happen during its return to normalcy.

Favorite Research Problems?

You know, I really don't know I love all my children. 

Enzyme Inhibitors 
One is that in potatoes you have starches converting into sugar and sugar can be converted to starch and some of the enzymes is one of them is known as invertase which converts ordinary sugar into glucose and fructose is present in potatoes and one of the key aspects of, or conditions what's the word I want to use, one of the key characteristics, is the word I want to use, of characterizing a potato an enzyme is to find its ph optimum. The break at which an enzyme acts is highly dependent on its ph so you get a sort of bell shaped curve when we tried for invertase we got two curves and yet we were pretty sure there wasn't two enzymes there. So I developed my theory of double ph optimum which states that, well in a very nutshell, that there is an inhibitor of this invertase, this enzyme which has the same characteristics as far as this ionization is concerned as that of the enzyme so that it acts maximumly at the same the ph at which the enzyme acts rationally so this will resign use the mathematics got to use double calculus and all kinds of fancy things like that to show that you get a double curve. 

This whole idea of an ambition led me to formulate a way of finding out if there are inhibitors substances in a living system, vegetables, plant, cell, animal which will prevent the enzyme from working and by using enzymes kinetics which I got very fascinated with you know you set up equations about the enzyme combining with what the thing is with the substrate which is going to act on and then breaking it up and then you set up equations for that.

Well I was able to develop an equation which would tell you whether there's an inhibitor in the enzyme and what the percentage inhibition was and sort of serendipitous aspect of this is, in modern medicine they are looking for enzyme inhibitors one of the many medicines are simply enzyme inhibitors and I dare say they must be using some of my work to fish out naturally occurring inhibitors some of these enzymes which can then be used for therapeutic purposes. This is speculation. What I'm saying right now but I dare to say it's true.

Enzyme purification 

I and a colleague from university of California. I had him help me, I was the senior author, wrote the first review ever on the principles and procedures for the isolation of enzymes which are still being looked at I think even in this day and age about 65 years later. 

Industrial Alcohol

Well we got out to California we went to work on producing industrial alcohol from grains which was never done before you produce alcohol from grains to drink it but the idea in those days since they had to use every bit of petroleum for vehicle purposes they didn't want to use it to produce industrial alcohol. 

So my boss got this idea of using it for from grains and this is been the basis of the subsequent 1970s and so on when we had the shortage of starting to think about using alcohol for gasoline and as you know the mid west you had this gasohol which is produced and a lot of the work is based on the work that I did especially I was more or less responsible for making sure we knew how much enzyme was doing the job and also my boss said why do you seen what happens if you don't cook the grains then it would be much cheaper. We wouldn't have to use energy. True, true cook the alcohol and cook the starch grains and so I looked into that and paper too is now still being cited as the foundation of the use of uncooked raw starch to prepare alcohol and now I believe there's actually a commercial process just which has been instituted 
in the last year or so for this purpose. 

Looking Back 

Been very delightful and I got this wonderful job in the middle of the depression and I always wanted to be involved in research and for the most part I enjoyed it very much. I suppose there might have been frustrations, "Hey why are they promoting that guy and not me?" and that sort of thing but I got there eventually and I enjoyed it very much. No complaints.

In about 9 years the Department of Agriculture will have been 150 years old and if I last that long and I'll be there I will have been associated with Department of Agriculture for half of its life and I think I was once interviewed I said I won't be there but later on I said by golly I'm gonna make it.