Globulins, cucurbit

Decorticated cucurbit seeds contain by weight about 35% protein. Traditionally, seed proteins are classified as globulins and albumins according to their solubility in certain aqueous solvents. Biochemically, oilseed globulins are generally considered storage proteins while albumins are believed to be metabolic (catalytic) proteins. 

A later study (45) indicates that cucurbitin from pumpkin has a molecular weight of TT2,000 dal tons that can be electrophoretically separated into subunits of 63,000 and 56,000 dal tons. Reduction of disulfides produces polypeptides of 36,000 and 22,000 dal tons. Globulins from six cucurbits examined chromatographically (46) have molecular weights of 220,000 to 260,000 dal tons that exhibit predominantly 10.4 - 11.2 S values (about 95% of the three globulin fractions). Cucurbitin from Cucumis sativus appears a tetramer of... 

From amino acid compositions, evaluations o7" the nutritional potentials of cucurbit meals and globulins can be calculated according to FA0/WH0 (54). The A E ratios, which are the amounts of each essential amino acid relative to the total amount of essential amino acids, are shown in Table II. These data indicate that, like most other oilseeds, cucurbit seeds are deficient in lysine and sulfur-containing amino acids. However, sulfur-containing amino acids are considerably high in CitrullI us colocynthis (egusi, ancestral watermelon) seed protein and exceed the suggested level in FA0/WH0 reference protein (55). 

Table II. Amino Acid Contentsa and A/E Ratios15 of Cucurbit Meals and Globulins...

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